Add extension action items vertical bar to the search results page

Created by: AlicjaSuska

Part of the tracking issue #16165, RFC 250

Description

Create the toggleable vertical bar on the search results page.

*Vertical view for the code-oriented pages is covered in the separate issue

Design details Figma

This issue should cover the following:

• add a vertical bar
• add icons (mdi:puzzle-outline) or (mdi:chevron-double-up) to the actions bar that toggle-open / close the vertical bar
• convert all action items to icons
• add tooltips + content of the tooltip used so far (action name / names, shortcuts etc.). Inactive extension should show 'not allowed' coursor on hover. No delay on the toolip.
• add hover to all elements of the bar
• add active state to the action items
• add a plus icon (mdi:plus) to the vertical bar. It should link to the extensions registry. Tooltip: 'add extensions'

Important note: action items bar shows all the extensions on all the pages - it means that extensions that are active on search results page will be visible but disabled on code-oriented pages and vice versa.