Add admin panel for user overview details

[ketura]

When people request a password reset, at the moment the only way to verify ownership is to quiz them on deck names and game history. While this isn't the best status quo, it's what we've got until email is properly incorporated.

In the meantime, add a form for bringing up a player's decks and game history, rather than requiring an admin do this manually in the db every time a password reset request is made.

In addition to this usage, there are other user management functions that are occasionally used that could be incorporated here. For example, game history export, mass deck export, grabbing a replay for a player who reported a bug but didn't include a replay link, or inspecting a deck for tournament eligibility.

Ideally this has three sections:

1. User Overview
   2. User flags
   3. Games played
   4. First game played
   5. Last game played
   6. Event participation?
   7. Link to download a csv of user-friendly game history
   8. Link to download a csv of user-friendly links to decklists
2. Player decks
   10. Two panes. Left pane is a list of deck names.
   11. Upon clicking an item in the left pane, right pane shows the deck contents (same content as what's on the deck sharing page).
   12. Right pane includes a link to the deck sharing URL that can be clicked or copied.
3. Player Game History
   14. Scrollable table of the last X matches by the player, with links to both their replay and their opponent's.
   15. Include most if not all of the game history table columns.
   16. Ideally this is paginated