The calendar renderer used a template for events.
Now moved as a configurable template to ease futur calendar changes.
This commit adds also a custom event to the calendar renderer so that custom
implementations have a way to re-render the event items within the calendar
after making internal changes to the event records.
We introduce also a new option for a field "filter_field" which allows to specify
the field of the model in which we will save the status of a filter.
This is preliminary changes in order to make the calendar view able to modify
the attendance status of a meeting and refresh the events to visually display
if the user is attending or not.
Task ID 2196775
COM PR: odoo/odoo#55190
ENT PR: odoo/enterprise#12196
UPG PR: odoo/upgrade#1532
Co-authored-by: Simon Genin (ges) <ges@odoo.com>
Co-authored-by: jeh-odoo <jeh@odoo.com>
