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
diff --git a/TODO-RELEASE b/TODO-RELEASE
index add44f1..3b31cde 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -25,3 +25,4 @@
 #
 #library		what		description / commit summary line
 update dependency to libosmocore > 1.5.1 for our use of osmo_sock_set_dscp()
+libosmo-mgcp-client  struct mgcp_client_conf ABI breackage
\ No newline at end of file