S60/Debugger: Add Bluetooth starter to Debugger

- Remove old rfcomm process handler from TrkGdbAdapter, use
  Bluetooth starter instead
- Synchronous connection, remove waitForTrkConnect()
- Move gdb start into Trk version answer, pass on
  settings id hint
- Prevent exit crash triggered by signal gdbProcessFinished()
- Set DebuggerNotReady correctly on AdapterStartFailed when no
  gdb is started yet