linux: create maintainer team

Now there are a few more folks who should get pinged on kernel changes:

$ nix-instantiate -E 'with import ./. {}; (map (x: x.github) linux.meta.maintainers)' --eval --strict
[ "TredwellGit" "mweinelt" "ma27" "nequissimus" "alyssais" "thoughtpolice" ]

Refs #140281

maintainers/team-list.nix

···
     scope = "Maintain Kodi and related packages.";
   };
 
+  linux-kernel = {
+    members = [
+      TredwellGit
+      ma27
+      nequissimus
+      qyliss
+    ];
+    scope = "Maintain the Linux kernel.";
+  };
+
   mate = {
     members = [
       j03

pkgs/os-specific/linux/kernel/manual-config.nix

···
         license = lib.licenses.gpl2Only;
         homepage = "https://www.kernel.org/";
         repositories.git = "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git";
-        maintainers = [
+        maintainers = lib.teams.linux-kernel.members ++ [
           maintainers.thoughtpolice
         ];
         platforms = platforms.linux;