Improve RTMP Driver Security

[kyle-fitzp]

Add authorization to RTMP driver. Require username, password, stream path to match between server and client.

[kyle-fitzp]

After some research, a couple options exist

1. Modify the FFmpeg source code. Might be difficult to maintain.
2. Create a custom RTMP server based on the FFmpeg RTMP server. (Currently leaning towards this option).