openvidu-browser: Reformat function checkSystemRequirements()
openvidu-browser: Reformat function checkSystemRequirements()

It was difficult to read and modify, and the "if/else" return logic
could be simplified.

Also the comments were outdated. Remove them and let the code speak
by itself.

OpenVidu/openvidu,OpenVidu/openvidu,OpenVidu/openvidu,OpenVidu/openvidu,OpenVidu/openvidu,OpenVidu/openvidu