2021-February-05 - Prerelease - 2.6.38@61629a3bb1

Update maps server table (#8761)

- rename table from 'map' -> 'map_index'
- rename a few columns to be more descriptive
- remove map_skin table, will not be needed
- remove description and preview columns from map table.
  If the game client knows where a map repo is located,
  it will be able to find the description and preview images
  by appending to 'preview.png' and 'description.html' to
  the repo URL (game client will fetch these directly)