Add breezy (brz), a successor to bazaar (bzr).

Breezy (brz) is a decentralized revision control system, designed to be
easy for developers and end users alike.

By default, Breezy provides support for both the `Bazaar
<https://www.bazaar-vcs.org>`_ and `Git <https://www.git-scm.com/>`_ file
formats.

To learn how to use Breezy, see the official documentation in the `doc`
directory or refer to the Bazaar documentation at
<https://www.breezy-vcs.org/doc/en/>.

Breezy is a friendly fork of the Bazaar (``bzr``) project, hosted on
http://bazaar.canonical.com/. It is backwards compatibility with
Bazaar's disk format and protocols. One of the key differences with
Bazaar is that Breezy also runs on Python 3.3 and later, in addition to
Python 2.7.

(rhialto)