cephadm: add a new funkypatch fixture based on mock.patch and pytest

cephadm: add a new funkypatch fixture based on mock.patch and pytest

This fixture acts like a combination of mock.patch and pytest's
monkeypatch fixture. It has the additional feature of automatically
finding and patching the same object imported in other modules.  If you
have 'from x import y', where y is a function or class, in both a.py and
b.py it will patch both instances (so long as both a and b are already
imported).
This behavior is useful for cephadm because of the heavy use of the
`from x import y` idiom and how cephadm is being actively refactored.

Signed-off-by: John Mulligan <jmulligan@redhat.com>