mgcp_client: drop a bunch of dead code

Remove public API that makes no sense anymore and is dead code.

I see the dropped API as a dead-end initial misconception of the early mgcp
client, and it doesn't really make sense to drag this stuff along. It has not
been used by osmo-msc,-bsc for a long time now, and just confuses the reader.

It is public API, yes, and older versions of osmo-msc / osmo-bsc will not be
able to compile against this, but even if it did, the resulting MGCP client
would not work with the current osmo-mgw: this API is still based on the
premise that the MGCP client dictates the MGW endpoint numbers, a concept that
cannot be used with the current osmo-mgw. Instead, osmo-mgw expects a
wildcarded endpoint upon CRCX and assigns its own endpoint names.

Also, the bts-base configuration is unused and a legacy of when osmo-bsc_mgcp
had explicit BTS and CN sides.

Change-Id: I98a9f1f17a1c4ab20cea3b08c7d21663592134d6
7 files changed