Add Bluez API to DBus XML parser/generator

Summary:
I created this tool in the hope it is helpful for others.
It generates DBus introspection XMLs out of the original Bluez DBUS api descriptions found at: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc .
Further plans are to also add a C++ generator.

Please have a look and share your thoughts. Thanks.

Reviewers: drosca

Reviewed By: drosca

Differential Revision: https://phabricator.kde.org/D21265