Bluetooth: begin testing infrastructure

Implement an XML-RPC server for both the Client (DUT) and Tester
based off the existing WiFi testing approach, with a server class
to proxy for them.

BUG=chromium:256771
TEST=simple test that instantiates both,
 verify xml-rpc server was running on both devices

Change-Id: Icbaf9409460f0d535c160f6a11f1db86f989f46a
Reviewed-on: https://gerrit.chromium.org/gerrit/62890
Reviewed-by: Scott James Remnant <keybuk@chromium.org>
Tested-by: Scott James Remnant <keybuk@chromium.org>
Commit-Queue: Scott James Remnant <keybuk@chromium.org>
8 files changed