Do not use computed fields in Suggestions

Instead of using computed fields, we set default values. This way, no
onchange call is needed anymore, and the total loading time is reduced.

On a test server, the following figures are obtained:
- `default_get`: ~140ms -> ~190ms
- `onchange`: ~600ms -> None
- `read`: 140 + 160 = ~200ms -> Unchanged

The loading time of the homepage drops from ~1.0s to ~0.4s, which is
perceptively faster.

models/oomusic_suggestion.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from odoo import api, fields, models
+from odoo import fields, models
 
 
 class MusicSuggestion(models.TransientModel):
@@ -11,41 +11,61 @@ class MusicSuggestion(models.TransientModel):
     name_albums = fields.Char("Name Albums", default="Albums")
 
     track_last_played = fields.Many2many(
-        "oomusic.track", string="Last Played", compute="_compute_track_last_played"
+        "oomusic.track",
+        string="Last Played",
+        store=False,
+        readonly=True,
+        default=lambda s: s._default_track_last_played(),
     )
     track_recently_added = fields.Many2many(
-        "oomusic.track", string="Recently Added Tracks", compute="_compute_track_recently_added"
+        "oomusic.track",
+        string="Recently Added Tracks",
+        store=False,
+        default=lambda s: s._default_track_recently_added(),
     )
     track_random = fields.Many2many(
-        "oomusic.track", string="Random Tracks", compute="_compute_track_random"
+        "oomusic.track",
+        string="Random Tracks",
+        store=False,
+        readonly=True,
+        default=lambda s: s._default_track_random(),
     )
 
     album_recently_added = fields.Many2many(
-        "oomusic.album", string="Recently Added Albums", compute="_compute_album_recently_added"
+        "oomusic.album",
+        string="Recently Added Albums",
+        store=False,
+        readonly=True,
+        default=lambda s: s._default_album_recently_added(),
     )
     album_random = fields.Many2many(
-        "oomusic.album", string="Random Albums", compute="_compute_album_random"
+        "oomusic.album",
+        string="Random Albums",
+        store=False,
+        readonly=True,
+        default=lambda s: s._default_album_random(),
     )
 
-    @api.depends("name_tracks")
-    def _compute_track_last_played(self):
-        self.track_last_played = [
+    def _default_track_last_played(self):
+        return [
             p["res_id"]
-            for p in self.env["oomusic.preference"]
-            .search(
-                [("play_count", ">", 0), ("res_model", "=", "oomusic.track")],
+            for p in self.env["oomusic.preference"].search_read(
+                fields=["res_id"],
+                domain=[("play_count", ">", 0), ("res_model", "=", "oomusic.track")],
                 order="last_play desc",
                 limit=10,
             )
-            .read(["res_id"])
         ]
 
-    @api.depends("name_tracks")
-    def _compute_track_recently_added(self):
-        self.track_recently_added = self.env["oomusic.track"].search([], order="id desc", limit=10)
+    def _default_track_recently_added(self):
+        return [
+            p["id"]
+            for p in self.env["oomusic.track"].search_read(
+                fields=["id"], domain=[], order="id desc", limit=10,
+            )
+        ]
 
-    @api.depends("name_tracks")
-    def _compute_track_random(self):
+    def _default_track_random(self):
         folder_sharing = (
             "inactive" if self.env.ref("oomusic.oomusic_track").sudo().perm_read else "active"
         )
@@ -57,14 +77,17 @@ def _compute_track_random(self):
         self.env.cr.execute(query)
         res = self.env.cr.fetchall()
 
-        self.track_random = [r[0] for r in res]
+        return [r[0] for r in res]
 
-    @api.depends("name_albums")
-    def _compute_album_recently_added(self):
-        self.album_recently_added = self.env["oomusic.album"].search([], order="id desc", limit=10)
+    def _default_album_recently_added(self):
+        return [
+            p["id"]
+            for p in self.env["oomusic.album"].search_read(
+                fields=["id"], domain=[], order="id desc", limit=10,
+            )
+        ]
 
-    @api.depends("name_albums")
-    def _compute_album_random(self):
+    def _default_album_random(self):
         folder_sharing = (
             "inactive" if self.env.ref("oomusic.oomusic_track").sudo().perm_read else "active"
         )
@@ -76,4 +99,4 @@ def _compute_album_random(self):
         self.env.cr.execute(query)
         res = self.env.cr.fetchall()
 
-        self.album_random = [r[0] for r in res]
+        return [r[0] for r in res]