Introduce a StartingTileLocation concept to the BoardConfiguration because this defines where the first play of a game MUST be played
Alter the DeterminePotentialPlayLocationsForNextWord implementation to be aware of the StartingTileLocation and use it to determine a valid play
All plays on the StartingTileLocation should be valid plays (only the first play gets to do it)
Still a to-do to write tests for this change
Changing GameState.PlayedWords to an IList instead of an IEnumerable since that collection will need to be modified