findAvailableDaemon
Finds an available daemon which can serve a runner with the given resource limit.
It is safe to continuously call this method until it returns a non-null value.
Return
The instance of LocallyTrackedDaemonHost representing the Docker daemon satisfying the resource limit, or null, if none exists.
Throws
if any of the above preconditions were not met.
if no daemon is able to satisfy the resource limit, regardless of its state.