PURPOSE
Improve mail template preview wizard by improve its views and displaying
more rendered fields. It helps users knowing what will be sent to customers.
SPECIFICATIONS
Rename template model to mail_template_preview to better match the mail
template namespace.
Remove _inherit on mail.template and instead choose fields to compute
and display. Indeed lot of fields are unnecessary or badly computed.
Instead just add fields on the wizard that depends on mail template
and will be computed based on mail_template_id field of wizard.
Improve error management.
LINKS
Task 2085912
PR #38708
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>