[IMP] gamification, website_forum : apply various improvements

- add menu to configure ranks in gamification tools because was missing
- move admin karma data in gamification : karma linked to gamification
  and not forum anymore
- fix rank computation : next_rank_id could never been recomputed correctly
  if rank are created in a karma ascending order.

Task ID : 1922159
PR #30988

addons/gamification/models/res_users.py

@@ -74,8 +74,10 @@ class Users(models.Model):
             old_rank = user.rank_id
             for i in range(0, len(ranks)):
                 if user.karma >= ranks[i]['karma_min']:
-                    user.rank_id = ranks[i]['rank'].id
-                    user.next_rank_id = ranks[i - 1]['rank'].id if i > 0 else False
+                    user.write({
+                        'rank_id': ranks[i]['rank'].id,
+                        'next_rank_id': ranks[i - 1]['rank'].id if i > 0 else False
+                    })
                     break
             if old_rank != user.rank_id:
                 user._rank_changed()

addons/gamification/views/gamification_karma_rank_views.xml

@@ -67,5 +67,7 @@
                 </form>
             </field>
         </record>
+
+        <menuitem id="gamification_karma_ranks_menu" parent="gamification_menu" action="gamification_karma_ranks_action" sequence="40"/>
     </data>
 </odoo>