By default, an event can be modified by any employee. This is also the
case for private events, displayed as "Busy" to other users. However,
since any user can modify an event, nothing prevents him to change the
privacy setting in order to be able to see the content.
This commit introduces a global record rule which only allows the
followers of an event to modify it.
opw-705079
Migration of all python code, mostly withtout chagnes. And adapting
xml files to guidelines.
On calendar.py, some changes have been perform to make the migration works :
- `_compute` method has been split into `_compute_dates`, `_compute_attendee` and `_compute_display_time`.
- remove unused method `onchange_partner_ids`, `check_partners_email`
- make `compute_rule_string` use a cache record instead of a value
dict to avoid crashes
- remove `new_invitation_token` method, and make it a default value on attendee creation
- add a default value on `day` field, otherwise the "Please select a
proper day of the month" exception is raised during the onchange
Yannick Tivisse