BSC_Tests: Start with much simpler tests at BSSAP / SCCP level

Rather than using the more complex RSL Emulation and BSSAP emulation
components, we attach to the RSL and BSSAP Codec Ports and send some
messages back and forth for low-level testing such as timeouts, response
to RACH requests, failure of MSC to react to CR requests, etc.
5 files changed