BSC LCLS: add bts-loop tests

Add basic establishment and teardown tests for 'bts-loop' mode of LCLS:
* add explicit vty init for desired LCLS kind
* add necessary IPA RSL MDCX functions
* explicitly pass LCLS kind as a parameter to shared
  functions (defaulting to 'mgw-loop')

Change-Id: I40e786b430591899c722d99d685db26efa868508
Related: OS#3659
3 files changed