Movement action

[foxfriends]

The movement action allows moving any number of warriors from a clearing to another adjacent clearing (if the mover rules at least one of the two clearings). The server should be able to determine which clearings can be moved between, and provide a actions move(From, To, Count) to the client for each pair of clearings, and each number of warriors in each.

Since all factions are able to move, make this as reusable as possible. No need to worry about the exceptions made for certain factions yet.

The frontend will then need to be updated to handle the move action, somehow allowing the player to choose how many warriors to move and sending the corresponding number back to the server.