Friends list

Create a SQL table that models the friendship relations

These columns will be needed
* PlyerFriendshipRelationId
* PlayerId
* BefriendedPlayerId
* CreationDate (when this row was created)

This relation will show what player's a given player has added to their friends list. The friendship is not necessarily mutual, as the player can add another without the other adding the first player.

The player should have a list of PlyerFriendshipRelations which will include all entries from the table where the PlyerId matches that of the player.

A new Object in the BE should also be created with the same names as the table uses.
Remember to update Player.BuildObjectFromReader() such that the "foreach (var player in result)" also adds the new relations to their PlyerFriendshipRelations list.