The MGCP_Test testsuite currenty lacks VTY access capabilities, lets
add them so that future testcases can access the VTY in order to change
options on the fly.
Depends: osmo-ttcn3-hacks Ife949c61156222de3026280071226ef6f5dbd959
Change-Id: If383f81af3306f8f5bdf50152498ae1303d390df
Related: OS#3807
Let's make sure we share common configuration between the test
suites and split the config file into a "default" part which is
used (but not copied) in the Docker images, and a "local" part
which is basically those overrides that the user (or docker image)
wants to do from the default.
Change-Id: I3db452e24e5238aa05254d903739c64d202e61db