Docs examples 12/14: Rework table, card, and dashboard panel examples

Part 12 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: table, card, dashboard panel. The members table example (with isRowHeader and stacked) sits under Behavior > Responsiveness, and the card metric example mirrors the real access token statistics cards from the personal access tokens page.

Safe to publish without the MRs after it.