Make Player Cards their own page

[tristengeven]

Currently player cards are a modified type of "post category". It would be ideal to have a separate definition for player cards so that they can be organized and created without interfering with blog post types.

[tristengeven]

Created PlayerIndex components mirroring BlogIndex ones. Next step is to correct how the Player page queries "posts". Instead of categorizing all of them, it needs to get only player posts.