Current situation
Experienced users do a lot of searches with various namespace combinations. Our namespace selection went from grid to list which makes selecting namespaces take a bit longer. To speed things up (even more than with the grid) the idea is to allow users to save their namespace search combinations.

Task
Adding a "bookmarking" functionality for namespace combinations, just like it's possible to do in recent changes.

Mocks
logged in

logged out

Acceptance criteria (needs to be separated into multiple tickets I assume)

• allow adding of namespace combinations as filters
• let the user pick a name for it (should only visible to that user)
• can be set as default
• can be deleted
• can be renamed
• all filters can be accessed from a place and when selected they appear as tags in the tag space

This also means that

• We get rid of the current checkboxes for "all" "help"...
• "remove all" and "add all" are added as buttons
• general help and talk pages are added in the filter space (for logged in users)
• and in the area for "saved filters" for not logged in users

Notes:
Can't guarantee that I thought of all criteria that should be listed here but I assume it's the majority and should be sufficient for an estimation.