Add setSystemFactoryDefault request

[bl0ggy]

Nothing to say about this. Just add a new ONVIF request.

[coveralls]

Coverage decreased (-4.9%) to 82.395% when pulling bb73538 on bl0ggy:add_setSystemFactoryDefault into 2a7f9fe on agsh:master.

[bl0ggy]

I added a test, but it covers less than before ?
I think coveralls has a bug haha, probably because I made multiple PRs.

[RogerHardiman]

Hi
Thanks for the tests.

There used to be a way to make the tests run against a real camera by setting HOSTNAME, PORT, USERNAME and PASSWORD as environment variables.
However I think it is broken at the moment.

But assuming it gets fixed, we would want to block the Reset (and also the Reboot commands) or our tests against a real camera would make the camera reboot and other tests would time out.

Anyway this is fine for the Mock server.