Feature: crm_resource: Implement --ban for moving resources away from nodes and --clear (replaces --unmove)

--move is now for moving _to_ a named --host (although --host may still be
omitted for backwards compatibility)

--ban is for moving _from_ a named host, or the current host if none is
provided

--move and --ban are logically equivalent when no --host is provided

--clear removes the constraints created by both --move and --ban