RCFilters UI: Define interaction states for filters

RCFilters UI: Define interaction states for filters

This patch sets up the ground for all three interaction types:
'subset', 'conflict' and 'coverage' as toggle-able properties
of the item and group models, and sets up the widgets' initial
logic abou their own "mute" state.

The patch includes the basic logic for two interactions:
- Subsets (and 'supersets' that are derived from them)
- Coverage

Direct conflict states will be defined in an upcoming commit.

Bug: T156864
Bug: T156861
Bug: T156860
Change-Id: If20bbe9f1442cfcfce046e56f6150b38dd3a4efc