Add superviserReception to rpc/superviser package

Add superviserReception to rpc/superviser package

boruta server requires IP address of the connected dryads to be saved
so that it can connect back to the Go RPC service they expose.

superviserReception wraps WorkerList in Superviser interface.
It saves IP address of a connection and registers a new Go RPC
service. The saved IP address is later used during call to Register.

Change-Id: I72f91d1c981e02ac13a07327b0b910e82a32fae9
Signed-off-by: Aleksander Mistewicz <a.mistewicz@samsung.com>
Reviewed-on: https://mcdsrvbld02.digital.local/review/49609
Reviewed-by: Maciej Wereski <m.wereski@partner.samsung.com>
Tested-by: Maciej Wereski <m.wereski@partner.samsung.com>