feat: apply new module format to lsp plugins

modules/lsp/lsp-signature/config.nix

@@ -0,0 +1,21 @@
+{
+  pkgs,
+  config,
+  lib,
+  ...
+}:
+with lib;
+with builtins; let
+  cfg = config.vim.lsp;
+in {
+  config = mkIf (cfg.enable && cfg.lspSignature.enable) {
+    vim.startPlugins = [
+      "lsp-signature"
+    ];
+
+    vim.luaConfigRC.lsp-signature = nvim.dag.entryAnywhere ''
+      -- Enable lsp signature viewer
+      require("lsp_signature").setup()
+    '';
+  };
+}