Allow players to set on their profiles their default color. An addition to this would be to let players rate the colors in case they join a room/game where their configured colors are already taken.
When a player enters/creates a game lobby:
* if the player's #1 ranked color is not yet taken, that will be the player's default color.
* if the player's #1 ranked color is already taken, then the player's #2 ranked color will be the player's default color. (and so on until the player is assigned a color from its configured color rankings)
* if the other player who has the #1 ranked color leaves the game or selects a different color, the player's color will automatically change to the #1 ranked color.