RCFilters: Add 'views' concept and a namespace view to RCFilters

RCFilters: Add 'views' concept and a namespace view to RCFilters

Enhanced RCFilters: Add the ability to filter by namespaces to RCFilters.
	🎉	🎁	🎊

- Add the ability to separate groups of filters by 'views'
- Add the first views as 'default' (for predefined filters)
  and 'namespace' as the list of namespaces.
- Add 'nsinvert' to namespace group
- Allow highlighting namespaces
- Allow searching on either view, depending on prefix
- Add a way to switch views by typing prefix, clicking the
  'Namespaces' button or clicking a tag (either namespace
  or filter tag, changes the view accordingly, and adds
  or removes the prefix from the input to stay consistent)
- Add an optional wrapper text for tags, so we can represent
  them with their respective prefixes and (if needed) with
  a special message for inverted state.
- Add unit tests and make pass
- Bonus: Fix issue with URL not updating (and not being updated)
  the inverted and highlight enabled states.

Bug: T159942
Bug: T163521
Bug: T164130
Change-Id: I7e83f0800cbeb289dfd3461c1c5a197c053147ca