[FIX] web: correctly init searchview when no action_id

the method prepare_dropdown_menu wasn't called when the searchview did
not have an action id.  This can cause problems in some cases (for
example, a crash in messaging when toggling the favorite menu)
[IMP] SO form clean the mess
[IMP] website_sale : improve domain for not set category in product from frontend  and remove other demo data of public categories
[FIX] web: add missing icon, add warning, fix deferred

* ir_actions_common should return a deferred : some widgets
  do not return a deferred in start, so it could be undefined.
  it now is always a deferred.
* add icon for diagram view + breadcrumb support. diagram view
  is so rare that it wasn't tested in the client refactoring.
  This patch adds an icon for diagram view, and better support for
  breadcrumbs
* add warning in debug mode print workflow: when no record is
  selected, display a warning instead of failing silently
[IMP] project,project_issue: follow tasks and issues that are ready for the next stage
[FIX] website: Odoo's social URLs
[FIX] website: typos
[IMP]Website Blog: Make Onboarding tour user friendly and change customize cover feature