Introduced server_service recover_streaming_appliers() interface
call which will be called in total order whenever streaming appliers
must be recovered. The call comes with two overloads, one which
can be called from client context (e.g. after SST has been received)
and the other from high priority context (e.g. view event handling).
The client context overload should be eventually be deprecated once
there is a mechanism to make provider signal that it has joined to
the cluster and will start applying events.