Deprecate Tags and Flags (doc update)

Apply official deprecation process for Tags and Flags
primitives that has been superseeded by Groups.

This change includes the update of the documentation that is
source of truth regarding the deprecated functionality.

OAMG-7262

docs/source/deprecation.md

@@ -13,7 +13,11 @@ the leapp standard library, etc. But don't cover deprecated functionalities
 from particular leapp repositories (e.g. the [elt7toel8](https://github.com/oamg/leapp-repository/tree/master/repos/system_upgrade/el7toel8) leapp repository). For
 such information, see [Deprecated functionality in the el7toel8 repository](el7toel8/deprecation.html#deprecated-functionality-in-the-el7toel8-repository).
 
-*Note: No new deprecation present yet.*
+## current upstream development <span style="font-size:0.5em; font-weight:normal">(till the next release + 6months)</span>
+
+- Reporting primitives
+    - **`leapp.reporting.Flags`** - The `Flags` report primitive has been deprecated in favor of the more general `Groups` one.
+    - **`leapp.reporting.Tags`** - The `Tags` report primitive has been deprecated in favor of the more general `Groups` one.
 
 ## What is covered by deprecation process in leapp?
 

leapp/reporting/__init__.py

@@ -9,6 +9,7 @@
 from leapp.models import fields, Model, ErrorModel
 from leapp.topics import ReportTopic
 from leapp.libraries.stdlib.api import produce
+from leapp.utils.deprecation import deprecated
 
 
 class Report(Model):
@@ -159,9 +160,29 @@ def __init__(self, value=None):
         self._value = value
 
 
-# To gradually switch from using Tags and Flags to using Groups make Tags and Flags aliases of Groups
-Tags = Groups
-Flags = Groups
+@deprecated(
+    since='2022-09-01',
+    message=(
+        'The primitive is deprecated as Tags and Flags have been joined into the Groups primitive.'
+        'Please use Groups for report message typing instead.'
+    )
+)
+class Tags(Groups):
+    def __init__(self, *args, **kwargs):
+        super(Tags, self).__init__(*args, **kwargs)
+
+
+@deprecated(
+    since='2022-09-01',
+    message=(
+        'The primitive is deprecated as Tags and Flags have been joined into the Groups primitive.'
+        'Please use Groups for report message typing instead.'
+    )
+)
+class Flags(Groups):
+    def __init__(self, *args, **kwargs):
+        super(Flags, self).__init__(*args, **kwargs)
+
 
 # To allow backwards-compatibility with previous report-schema
 # Groups that match _DEPRECATION_FLAGS will be shown as flags, the rest as tags