Ease the understanding of the notifications sent when users are assigned to an
activity or a model (task, lead, ...).
Technical note:
- the customization of data sent to the email layout template (here subtitles)
should be done by overriding
mail_thread._notify_by_email_prepare_rendering_context on the model.
But in this case, we send an activity (ex.: todo) for a model (ex.: crm.lead)
which involves 2 models. Data from both models must be sent to the template
layout. To solve this problem an optional parameter to
mail_thread.message_notify has been added: subtitles. This allows the
caller which knows about the 2 models to set the values for subtitles for
the template.
- mail_activity._render_notify_header has been added to render the subject and
subtitles using the language of the recipients through the context lang
variable.
- a generic mail notification template has been added and the specific
mail_notification_paynow has been derived from it as the only change is the
handling of the signature.
Task-2801600
Part-of: odoo/odoo#88466
Pierre-Yves Dufays
a577afc75e