R1:1bbdfa60c7c6

Build PhabricatorTagView

Summary:
Builds out most of the non-hover-stuff from `overview-hovercards.png`. Things I didn't build:

- Tokens (I like them a lot but don't want to scope creep)
- Functions (backend mess / future work)
- Icons for tags.
- Tags with pointy ends and holes in them (an earlier mock had this I think but they're gone on final)
- The cyaney color for "Sporadic" since I just noticed it while typing this up.

Test Plan: Looked at UIExample page.

Reviewers: chad

Reviewed By…