backend docs #1732
Description
there are no docs about backend and/or coordinator
although the WasabiDoc should stay client focused,
there currently is no documentation about the backend & coordinator, also not in the main repo https://github.com/WalletWasabi/WalletWasabi/tree/master/WalletWasabi.Documentation (WalletWasabi/WalletWasabi#9139)