Odoo Release Updates

[FIX] html_builder, mass_mailing: fix mass_mailing snippets

[IMP] mass_mailing: remove masonry templates

[FIX] mass_mailing: ensure correct width for processing element

[IMP] mass_mailing: rename mismatched files, classes and registry

[IMP] mass_mailing: remove unused class `o_mail_no_resize`

[FIX] mass_mailing: allow reapplying a background image when removing it

[IMP] mass_mailing: allow converting a s_image which is a snippet descendant

[IMP] html_builder: allow empty `applyTo` for addProductOption

[FIX] mass_mailing: fix mass_mailing snippets

[REF] html_editor: split color plugin in two

[IMP] mass_mailing: fix mobile preview

[REF] html_builder, *: update `assets_edit_frontend` bundle name

[IMP] mass_mailing: sort out style assets to reduce loading time

[FIX] mass_mailing, html_editor: mass_mailing refactoring follow up

[IMP] html_editor, mail, mass_mailing: add option to allow checklist

[IMP] mass_mailing: fix scrolling during drag&drop

[FIX] mass_mailing: update html_builder asset inclusion

[IMP] mass_mailing: improve onboarding in an empty email

[FIX] html_builder, mass_mailing: add defaultImageMimetype config

[FIX] html_builder, html_editor, *: fix scss broken assets dependencies

[FIX] mass_mailing: only display resize option on img-fluid images

[REF] html_editor,web_editor,*: move scss assets from web_editor to html_editor

[IMP] mass_mailing: remove web_editor dependencies

[IMP] google_gmail, miscosoft_outlook: allow using IAP instead of local credentials

[IMP] *: use the "icons fonts" sub-asset-bundle in all asset bundles

[REF] mass_mailing, *: use html Builder instead of OdooEditor

[IMP] mass_mailing: reorganize style files

[IMP] mass_mailing: design option for margin bottom on paragraphs and headings