feat: [#654] new registration confg section

Registration Disabled:

```toml
```

Registration without email option:

```toml
[registration]
```

Registration optionally including an email address:

```toml
[registration]
[registration.email]
```

Registration with  email:

```toml
[registration]
[registration.email]
required = true
```

Registration with optional email, but if email is supplied it is verified:

```toml
[registration]
[registration.email]
verified = true
```

Registration with email and email is verified:

```toml
[registration]
[registration.email]
required = true
verified = true
```

TODO: remove old settings and use the new ones.

share/default/config/index.container.mysql.toml

@@ -15,3 +15,5 @@ connect_url = "mysql://root:root_secret_password@mysql:3306/torrust_index"
 port = 1025
 server = "mailcatcher"
 
+[registration]
+[registration.email]

share/default/config/index.container.sqlite3.toml

@@ -14,3 +14,6 @@ connect_url = "sqlite:///var/lib/torrust/index/database/sqlite3.db?mode=rwc"
 [mail.smtp]
 port = 1025
 server = "mailcatcher"
+
+[registration]
+[registration.email]

share/default/config/index.development.sqlite3.toml

@@ -12,3 +12,6 @@ threshold = "info"
 #[net.tsl]
 #ssl_cert_path = "./storage/index/lib/tls/localhost.crt"
 #ssl_key_path = "./storage/index/lib/tls/localhost.key"
+
+[registration]
+[registration.email]

share/default/config/index.private.e2e.container.sqlite3.toml

@@ -20,3 +20,6 @@ connect_url = "sqlite:///var/lib/torrust/index/database/e2e_testing_sqlite3.db?m
 [mail.smtp]
 port = 1025
 server = "mailcatcher"
+
+[registration]
+[registration.email]

share/default/config/index.public.e2e.container.mysql.toml

@@ -18,3 +18,6 @@ connect_url = "mysql://root:root_secret_password@mysql:3306/torrust_index_e2e_te
 [mail.smtp]
 port = 1025
 server = "mailcatcher"
+
+[registration]
+[registration.email]

share/default/config/index.public.e2e.container.sqlite3.toml

@@ -18,3 +18,6 @@ connect_url = "sqlite:///var/lib/torrust/index/database/e2e_testing_sqlite3.db?m
 [mail.smtp]
 port = 1025
 server = "mailcatcher"
+
+[registration]
+[registration.email]

src/config/v2/mod.rs

@@ -5,11 +5,13 @@ pub mod image_cache;
 pub mod logging;
 pub mod mail;
 pub mod net;
+pub mod registration;
 pub mod tracker;
 pub mod tracker_statistics_importer;
 pub mod website;
 
 use logging::Logging;
+use registration::Registration;
 use serde::{Deserialize, Serialize};
 
 use self::api::Api;
@@ -25,53 +27,77 @@ use super::validator::{ValidationError, Validator};
 use super::Metadata;
 
 /// The whole configuration for the index.
-#[derive(Debug, Default, Clone, Serialize, Deserialize, PartialEq)]
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct Settings {
     /// Configuration metadata.
+    #[serde(default = "Settings::default_metadata")]
     #[serde(flatten)]
     pub metadata: Metadata,
 
     /// The logging configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_logging")]
     pub logging: Logging,
 
     /// The website customizable values.
-    #[serde(default)]
+    #[serde(default = "Settings::default_website")]
     pub website: Website,
 
     /// The tracker configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_tracker")]
     pub tracker: Tracker,
 
     /// The network configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_network")]
     pub net: Network,
 
     /// The authentication configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_auth")]
     pub auth: Auth,
 
     /// The database configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_database")]
     pub database: Database,
 
     /// The SMTP configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_mail")]
     pub mail: Mail,
 
     /// The image proxy cache configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_image_cache")]
     pub image_cache: ImageCache,
 
     /// The API configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_api")]
     pub api: Api,
 
+    /// The registration configuration.
+    #[serde(default = "Settings::default_registration")]
+    pub registration: Option<Registration>,
+
     /// The tracker statistics importer job configuration.
-    #[serde(default)]
+    #[serde(default = "Settings::default_tracker_statistics_importer")]
     pub tracker_statistics_importer: TrackerStatisticsImporter,
 }
 
+impl Default for Settings {
+    fn default() -> Self {
+        Self {
+            metadata: Self::default_metadata(),
+            logging: Self::default_logging(),
+            website: Self::default_website(),
+            tracker: Self::default_tracker(),
+            net: Self::default_network(),
+            auth: Self::default_auth(),
+            database: Self::default_database(),
+            mail: Self::default_mail(),
+            image_cache: Self::default_image_cache(),
+            api: Self::default_api(),
+            registration: Self::default_registration(),
+            tracker_statistics_importer: Self::default_tracker_statistics_importer(),
+        }
+    }
+}
+
 impl Settings {
     pub fn remove_secrets(&mut self) {
         self.tracker.token = ApiToken::new("***");
@@ -101,6 +127,54 @@ impl Settings {
     pub fn to_json(&self) -> String {
         serde_json::to_string_pretty(self).expect("Could not encode JSON value")
     }
+
+    fn default_metadata() -> Metadata {
+        Metadata::default()
+    }
+
+    fn default_logging() -> Logging {
+        Logging::default()
+    }
+
+    fn default_website() -> Website {
+        Website::default()
+    }
+
+    fn default_tracker() -> Tracker {
+        Tracker::default()
+    }
+
+    fn default_network() -> Network {
+        Network::default()
+    }
+
+    fn default_auth() -> Auth {
+        Auth::default()
+    }
+
+    fn default_database() -> Database {
+        Database::default()
+    }
+
+    fn default_mail() -> Mail {
+        Mail::default()
+    }
+
+    fn default_image_cache() -> ImageCache {
+        ImageCache::default()
+    }
+
+    fn default_api() -> Api {
+        Api::default()
+    }
+
+    fn default_registration() -> Option<Registration> {
+        None
+    }
+
+    fn default_tracker_statistics_importer() -> TrackerStatisticsImporter {
+        TrackerStatisticsImporter::default()
+    }
 }
 
 impl Validator for Settings {

src/config/v2/registration.rs

@@ -0,0 +1,54 @@
+use serde::{Deserialize, Serialize};
+
+/// SMTP configuration.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct Registration {
+    /// Whether or not to enable email verification on signup.
+    #[serde(default = "Registration::default_email")]
+    pub email: Option<Email>,
+}
+
+impl Default for Registration {
+    fn default() -> Self {
+        Self {
+            email: Self::default_email(),
+        }
+    }
+}
+
+impl Registration {
+    fn default_email() -> Option<Email> {
+        None
+    }
+}
+
+/// SMTP configuration.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct Email {
+    /// Whether or not email is required on signup.
+    #[serde(default = "Email::default_required")]
+    pub required: bool,
+
+    /// Whether or not email is verified.
+    #[serde(default = "Email::default_verified")]
+    pub verified: bool,
+}
+
+impl Default for Email {
+    fn default() -> Self {
+        Self {
+            required: Self::default_required(),
+            verified: Self::default_verified(),
+        }
+    }
+}
+
+impl Email {
+    fn default_required() -> bool {
+        false
+    }
+
+    fn default_verified() -> bool {
+        false
+    }
+}