S2 PC node preparation

The S2 PC node must be configured to use a correct radio network group ID.

If the S2 radio group is migrated from B2 then the existing S2 PC node shall be used without any modifications.

In case there is yet no S2 PC node for some reason, the S2 PC node must have the correct radio network set as described in S2 Init Node. Please observe that all the nodes belonging to a given radio network must have the same group ID.