treewide: take maintainership from Karel

treewide: take maintainership from Karel

Both of us were working for Turris and using these devices on daily basis.
A few of these packages are still required and used by Turris. It would be great if
Turris people will take maintainership of these packages, but if they decide not to,
I can step in and take them.

Since Karel switched from using OpenWrt to NixOS and hopefully, I didn't reveal some
secret here, let's take maintainership of his packages.

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>