This commit will improve the wording and the layout of the invitation
email sent to the users getting access to the portal. The signup link of
the email will now be a button that emphasizes the call-to-action.
We will also provide in the email another link that will allow the user
to access the login page. This commit will also improve the wording of a
placeholder in the portal backend.
task-2573334
closesodoo/odoo#74210
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>