[Feature Request] Select FFmpeg location and prevent use of the bundled version

[jesuscc1993]

I'm submitting a...

[ ] Regression 
[ ] Bug report  
[x] Feature request

I already have FFmpeg installed as it's a dependency of other software I use. It makes no sense to me to have it twice. The app should let us pick a location for FFmpeg in case it's already installed and let us delete the bundled version.