Move Characters to a seperate collection.

[MrNen]

Currently characters and accounts are stored in the same collection despite being two completely different document types with different schemas which can cause issues with filtering. Separating them into separate collections would ease the logic of accessing and modifying them as well as validation.

[Lazrius]

Fixed in aaac8d1a5436ff8b86199bf3ea586b8610c9f6df