[IMP] email_template: body_html is now an html file, not a text file anymore.
Now that tools.mail.html_sanitize() has been detroyed, there is
no need anymore to keep this field as a text field.
[IMP] [ADD] website: added base for template designer.

[ADD] website: email_template: added website_link field, a link to edit the template
directly in the website
[ADD] website_mail: added controller and page to edit templates. They are still jinja
templates editable in the website. Not qweb templates.
[ADD] website_mail: JS file and editor override to enable only certain snippets. Those
are still to add, but will be base templates for email.
[IMP] website: improved the addition of editor JS in the template header to be able
to add JS file that override the editor without having to hack everything in the
template.
[MERGE] Sync with main website-al branch
[ADD] website_mail: template designer: added some snippets for template design
[MERGE] Sync with main website-al branch
[IMP] website_mail: improved email template snippets + added comparison / three columns / big pictures + some improvements in the page layout of template designer
[MERGE] Sync with website-al
[IMP] website_mail: template designer: improved button snippet
[CLEAN] website_mail: template designer: cleaned a bit the snippets to remove section tag
[MERGE] Sync with website-al
[IMP] website/website_sale: Use group to display shipping address in frontend like the backend. Use group for product facet caracteristique (backend/frontend). Customize templates is displayed function of groups of ir.ui.view templates.
[MERGE] [IMP] [ADD] website: added a page for email.template designer. This page allows to customize the html content of the email.template using the website editor. Specific snippets have been developed to be used in the templates. Indeed the classic snippets using complex html5 and css are not correctly rendered inside email clients.

[IMP] email_template: body_html is now a valid html file. As the html_sanitize is now basically destroyed, we can use an html field instead of a text one. Moreover, issues in the template will be seen directly and not when sending emails. Top cool.

[ADD] website: email_template: added website_link field, a link to edit the template
directly in the website
[ADD] website_mail: added controller and page to edit templates. They are still jinja
templates editable in the website. Not qweb templates.
[ADD] website_mail: JS file and editor override to enable only certain snippets. Some snippets have been implemented, based on the website editor snippets, but using tables and inline style instead of css and complex html5 formatting.
[IMP] website: improved the addition of editor JS in the template header to be able
to add JS file that override the editor without having to hack everything in the
template.

[TODO]
- verify the snippets in outlook
- check for snippet customize
- improve the layout of the template designer page