RATIONALE
Improve usage of composer in comment or email mode: support batch-posting in
comment, support more configuration from templates, improve global model.
SPECIFICATIONS
Change 'auto_delete_message' into 'auto_delete_keep_log' that has the inverse
meaning. Indeed it is unclear what 'auto_delete_message' really does. It is
used when automatically removing emails sent through mass mailing, to know
if message created through inherits are kept or not. Purpose of keeping them
is to have a log on the document. Deleting the message therefore removes the
log.
In this commit we change the meaning to something positive, keeping logs being
clearer when choosing which option to activate. Functional usage of the field
itself does not change with this commit.
Task-3035101 (Mail: Support batch-posting from composer)
Part-of: odoo/odoo#99482
Thibault Delavallée
9140ce06c3