Improve head to head section

[danbugs]

Describe the solution you'd like
Currently, the head-to-head section is very basic. There's tons of improvements that could be made to it, like (these are listed in order or priority):
(1) rn, we are querying based on the opponent_tag_with_prefix - this is terrible because if someone does just as much as change their prefix, they will show up as a different player in the head-to-head. We should query based on ID - I don't remember specifically why I didn't do that in the past, but it might have been something related to entrant IDs vs. actual user IDs. Perhaps, we can use game data (which does have IDs) to make that better by correlating it back to the set.
(2) display list of sets they've played.
(3) visual - make it look nicer.
(4) allow clicking on the opponent to view their profile (would be easy if we had opponent IDs).

Other than that, it could be cool to make displays for smt like: "your bracket demon" (i.e., whoever beats you the most), "you are a bracket demon to" (i.e., whoever you beat the most), etc.

Additional context
n/a

[CERLgit]

Going to look into this one