feat(tazjin/tverskoy): Add dunst configuration

This one is basically taken from some gist linked in the official
dunst readme and makes nice little boxes.

Change-Id: I5bee8488f333dcc2f7040b741729065ef8617ae0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3767
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI

users/tazjin/nixos/tverskoy/default.nix

@@ -367,6 +367,15 @@ in lib.fix(self: {
         lockCmd = "${screenLock}/bin/tazjin-screen-lock";
       };
 
+      services.dunst.enable = true;
+
+      xdg.configFile."dunst/dunstrc" = {
+        source = depot.users.tazjin.dotfiles.dunstrc;
+        onChange = ''
+          ${pkgs.procps}/bin/pkill -u "$USER" ''${VERBOSE+-e} dunst || true
+        '';
+      };
+
       systemd.user.startServices = true;
     };