[media-workshop] DVB demux improvements brainstorm section

I'd like to propose a theme with regards to DVB demux improvements.

While we did a lot of work at the frontend API, the DVB API is almost the same as it were in 2005, lacking some interesting functionalities.

The idea here is to have a brainstorm section in order to discuss some improvements, like: - add support for mmapped streams; - add support for dmabuf; - allow multiple sections to be filtered on the same PID; - allow multiple sections to be filtered at the same file descriptor.