Use consistent timestamp style

[graue]

Bookwyrm inconsistently uses relative dates ("10 months ago") and exact dates ("Jul 4") in the same interface. At a glance, I couldn't tell what order these comments were in. I had to do mental math to know which comment was posted first. Also, hovering the cursor didn't show the full date, which would have helped.

(Now I see that one of them says "started reading" and the other says "finished reading," but that escaped my notice before.)

The solution I'd like
Consistently use relative or absolute dates within an area of the UI, and if a date shown isn't the full date, allow hovering (or tapping on mobile) to see the full date.

Alternatives I've considered
While not my preference, the display could be kept as is but allow hovering/tapping to see the full date.