MCAP: Add a test tool for MCAP

* Add a command line tool for MCAP related tests
* This tool can access the Bluetooth stack via a command line program
* Type "help" to obtain a list of available console commands in this
  Bluetooth
* Bluetooth must be disabled when this tool is running

Bug: 37867299
Test: make, PTS MCAP test
Change-Id: I106e6625ee8a29b7fdad88cdfeb99419054ef771