refactor(modules): reduce host repetition

modules/cache.nix

@@ -0,0 +1,11 @@
+{...}: let
+	caddyLib = import ./_lib/caddy.nix;
+in {
+	den.aspects.cache.nixos = {
+		services.caddy.virtualHosts =
+			caddyLib.mkTailscaleVHost {
+				name = "cache";
+				configText = "reverse_proxy localhost:32843";
+			};
+	};
+}