modules/koillection: init

Currently fails to build as the frontend can't be built (due to using
Yarn's v2 lockfile format).

modules/default.nix

@@ -4,6 +4,7 @@
   amdgpu-pwm = ./services/hardware/amdgpu-pwm.nix;
   betanin = ./services/web-apps/betanin.nix;
   dunst = ./services/x11/dunst.nix;
+  koillection = ./services/web-apps/koillection.nix;
   porkbun-ddns = ./services/networking/porkbun-ddns.nix;
   radeon-profile-daemon = ./services/hardware/radeon-profile-daemon.nix;
 }