denature: video encoding needs file extension on path name

- Hacky fix symlinking through
- Technical change needed in generation of stream file names (I think)

Signed-off-by: Wolfgang Richter <wolf@cs.cmu.edu>
Merge branch 'encoder-path-extension-fix' of github.com:theonewolf/GigaSight into theonewolf-encoder-path-extension-fix