Docs examples 13/14: Rework avatar, badge, label, and token examples

Part 13 of 14 in the stack that splits up the approved draft !6295 (closed) into reviewable pieces. The content is exactly what was reviewed there; I've only sliced it.

Related to #3575.

Pages: avatar, avatar group, badge, label, token, skeleton loader. Realistic content (named users shared with the table example, real status badges, project topics for tokens), contextual placement, and unique example titles.

Safe to publish without the MRs after it.