Added support for Google´s Bumble Bluetooth Controller stack - #2

The backend supports direct use with Bumble. The HCI Controller is managed by the Bumble stack and the transport layer can be defined by the user (e.g. VHCI, Serial, TCP, android-netsim).

Pull Request Guidelines for Bleak

Before you submit a pull request, check that it meets these guidelines:

1. If the pull request adds functionality, the docs should be updated.
2. Modify the CHANGELOG.rst, describing your changes as is specified by the
   guidelines in that document.
3. The pull request should work for Python 3.9+ on the following platforms:
   • Windows 10, version 16299 (Fall Creators Update) and greater
   • Linux distributions with BlueZ >= 5.55
   • OS X / macOS >= 10.13
4. Squash all your commits on your PR branch, if the commits are not solving
   different problems and you are committing them in the same PR. In that case,
   consider making several PRs instead.
5. Feel free to add your name as a contributor to the AUTHORS.rst file!