[IMP] event: add a cron that clean the event pipeline

The cron will move every ended events in the next "ended stage"
We inherit from `ir.autovacuum`, so the method `power_on` is called one time per day.

Task #2088538

addons/event/models/__init__.py

@@ -6,3 +6,4 @@ from . import event_mail
 from . import event_stage
 from . import res_config_settings
 from . import res_partner
+from . import ir_autovacuum

addons/event/models/ir_autovacuum.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+from odoo import api, models, fields
+
+
+class AutoVacuum(models.AbstractModel):
+    _inherit = 'ir.autovacuum'
+
+    @api.model
+    def power_on(self, *args, **kwargs):
+        """
+        Cron which drags all events which end date is < now (= passed)
+        into the first next (by sequence) stage defined as "Ended"
+        (if they are not already in an ended stage)
+        """
+        ended_events = self.env['event.event'].search([('date_end', '<', fields.Datetime.now()), ('stage_id.pipe_end', '=', False)])
+
+        if ended_events:
+            ended_events.action_set_done()
+
+        return super(AutoVacuum, self).power_on(*args, **kwargs)