feat(codec): gethwconfig

[tony-go]

First shot: #169

[tony-go]

After a first attempt, it seems that enabling hardware accelerators is not straightforward.

Some of them can be linked statically, while others must be linked dynamically. In the latter case, we would need to require users to have the appropriate system libraries, which could include various drivers. This would significantly change how the bare-ffmpeg module is consumed.

Since this is not a top priority at the moment, we will pause this effort and resume it later.

Ref: https://trac.ffmpeg.org/wiki/HWAccelIntro