feat: add roundcube

feat: flake.lock update

sp-modules/roundcube/flake.nix

@@ -0,0 +1,9 @@
+{
+  description = "Roundcube is a web-based email client.";
+
+  outputs = { self }: {
+    nixosModules.default = import ./module.nix;
+    configPathsNeeded =
+      builtins.fromJSON (builtins.readFile ./config-paths-needed.json);
+  };
+}