Add mappings for media keys

[sasha0552]

Related: neutrinolabs/xrdp#3022 Fixes: neutrinolabs/xrdp#1725 Fixes: #211

[tim-gromeyer]

Any plans on merging this?

[sasha0552]

Just a heads up, I have another branch that has been adapted for neutrinolabs/xrdp#3039. But those changes have not been tested yet.

https://github.com/sasha0552/xorgxrdp/tree/media-keys

I kind of dislike the fact that there is still special handling for certain keys.

I don't have much time these days, hopefully I can carve out more time for this and PR for relative input in the next week or so.

[matt335672]

@sasha0552 - I'll pick this one up if you don't mind.

I've found a few problems with neutrinolabs/xrdp#3039 in testing related directly to the (currently unused) keycode interface. I'll get those fixed in devel first.

[matt335672]

Superceded by #316 which is now merged.