Add ONVIF control of Plugin for network PTZ Controllers

[Nwachinyere]

Allow hardware control of plugin through ONVIF, with the option to set port number, username and password, and a feed of current PTZ Camera being controlled with name, or Just the name and IP address.

[zapy85]

This would be a great feature for those cameras that does not support VESCA like Hikvision for ex.
I have a camera available if you would like to give this a try, the onvif protocol is available so i don't think it would be that hard to implement,