Support shared osmo-mgw process between osmo-msc and osmo-bsc in the same host
In development systems as well as in embedded products where we run osmocom's network-in-the-box, it's pretty convenient to run only one osmo-mgw process and have osmo-msc and osmo-bsc both use it. We should document in here what's needed to achieve that, and document how a config file for osmo-mgw osmo-msc and osmo-bsc would look like in this scenario.
I came a bit further here. I managed to get MSC_Tests.TC_lu_and_mt_call passed with the dynamic endpoint. However. I did not find out yet how to assign an endpoint. I think it would be enough to just replace the * in the string with a 1. Currently I am replacing the whole endpoint name, which is a little too much. Also I do not understand how the BSC tests exactly do that.