[feature] Add remove command

[cromefire]

It would be really nice if there would be a remove command similar to the remove command in hdr10plus_tool that removes dolby vision metadata from the stream. I have some files with seemingly damaged dolby vision metadata, so it would be nice to be able to remove it without needing to transcode them.

[quietvoid]

This is already supported through demux.
But maybe it could be worth having a remove subcommand as well.

As the NALUs are known, FFmpeg can be used to filter out type 62/63 as well.

[cromefire]

You are completely right didn't notice the little notice:

Also can be used to remove the RPUs from an HEVC file.

Maybe an example with a remove heading in the README or a remove "shortcut" could be nice though. Because right now from the README I'm not quite sure whether just a normal demux already removes if or whether I need any specific flag or so, because from the description it only removes the EL, but I have files with profile 8.1, so as far as I understand there is no EL. Might just be a little deficiency in documentation.

Edit: It seems the demux command works, so basically a remove command would only need a mapping of --output to --bl-out and set --el-out to /dev/null