Purpose
=======
Add the possibility to only synchronize one specific event of
a user calendar instead of syncing the whole calendar.
Specification
=============
In certain cases, we do not want to synchronize the whole user
calendar with all the events and recurrences but only a specific
event. For example, in appointment, to retrieve the generated
google meet url of a specified event.
To perform the single event synchronization a synchronization
token is needed, meaning we cannot do a single event
synchronization prior to a full calendar synchronization as it
is the full sync which generates the temporary sync token.
To prevent the need of doing a full sync before a single event sync,
the permanent synchronization token is been used instead of
the temporary one when performing a single event synchronization.
Task-3285601
Part-of: odoo/odoo#133921
amdi-odoo
a3eed99161