[MOV] calendar: move activity (type) code and views

Purpose is to have one file / model, easier when searching for inherited parts
of the code and see at a glance various usage of those models.

Spotted during Task-2207626 (Rating: Delay rating notification to ease feedback)

Part-of: odoo/odoo#98661

addons/calendar/models/__init__.py

@@ -12,4 +12,5 @@ from . import calendar_event_type
 from . import calendar_recurrence
 from . import mail_activity
 from . import mail_activity_mixin
+from . import mail_activity_type
 from . import res_users

addons/calendar/models/mail_activity.py

@@ -1,14 +1,9 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from odoo import api, models, fields, tools, _
+from odoo import models, fields, tools, _
 from odoo.tools import is_html_empty
 
-class MailActivityType(models.Model):
-    _inherit = "mail.activity.type"
-
-    category = fields.Selection(selection_add=[('meeting', 'Meeting')])
-
 
 class MailActivity(models.Model):
     _inherit = "mail.activity"

addons/calendar/models/mail_activity_type.py

@@ -0,0 +1,10 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import models, fields
+
+
+class MailActivityType(models.Model):
+    _inherit = "mail.activity.type"
+
+    category = fields.Selection(selection_add=[('meeting', 'Meeting')])

addons/note/models/__init__.py

@@ -2,5 +2,6 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from . import mail_activity
+from . import mail_activity_type
 from . import note
 from . import res_users

addons/note/models/mail_activity.py

@@ -4,12 +4,6 @@
 from odoo import models, fields
 
 
-class MailActivityType(models.Model):
-    _inherit = "mail.activity.type"
-
-    category = fields.Selection(selection_add=[('reminder', 'Reminder')])
-
-
 class MailActivity(models.Model):
     _inherit = "mail.activity"
 

addons/note/models/mail_activity_type.py

@@ -0,0 +1,10 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import models, fields
+
+
+class MailActivityType(models.Model):
+    _inherit = "mail.activity.type"
+
+    category = fields.Selection(selection_add=[('reminder', 'Reminder')])