*: website_event, website_forum, website_livechat, website_mass_mailing,
website_slides
This commit permits to reduce the risk to have a wrong h1 tag or
multiple h1 tags on the same page. This commit replaces some h1 tags
with a h2 in snippets. In addition, this commit removes some font sizes
written in the style attribute and replaces them with a font size class
now that they are possible to use and edit as an user.
task-1958098
Part-of: odoo/odoo#129791
Co-authored-by: qsm-odoo <qsm@odoo.com>
