mgcp_client: allow to reset endpoints on startup

Depending on the usecase of osmo_mpcg_client it may be helpful to send a
DLCX to certain endpoints. Usually this would be a wildcarded endpoint
that resets the entire trunk to drop lingering RTP flows which may still
present after a restart/crash, but it might be also a group of specific
endpoints. The user may specify an arbitrary amount of endpoints where
the mgcp client will send a DLCX to. It does not matter if the endpoints
are wildcarded or not.

Change-Id: I47e7ff858d5067b46d52329be5f362ff61c0dff8
Related: SYS#5535
5 files changed