This commit adds a way to configure scheduled emails on events. It replaces
existing automatic emails at confirmation and subscription. It proposes to
configure some schedulers, based on subscription or event, using a template
and a configurable timedelta.
A cron is added that regularly checks for event mailing schedulers to execute
and launch them. The granularity of send emails is therefore limited to the
granularity of the cron, aka 1 hour.
[TEST] Added tests for this feature.
Also cleaned a bit event, country_id is now a pure related instead
of a computed field trying to be a related. Also removed default templates
on event category. Configuration in the event itself should be easy
enough for most use cases.
Mahendra barad
ad48bf6d7d