feat(dev-infra): standard CLI commands using yargs (#36326)

Creates a standard model for CLI commands provided by ng-dev.
Allows for us to have any of the tools/scripts extend to be
included in the ng-dev command, or be standalone using the same
yargs parser.

PR Close #36326

dev-infra/pullapprove/BUILD.bazel

@@ -3,6 +3,7 @@ load("@npm_bazel_typescript//:index.bzl", "ts_library")
 ts_library(
     name = "pullapprove",
     srcs = [
+        "cli.ts",
         "group.ts",
         "logging.ts",
         "parse-yaml.ts",
@@ -16,9 +17,11 @@ ts_library(
         "@npm//@types/node",
         "@npm//@types/shelljs",
         "@npm//@types/yaml",
+        "@npm//@types/yargs",
         "@npm//minimatch",
         "@npm//shelljs",
         "@npm//tslib",
         "@npm//yaml",
+        "@npm//yargs",
     ],
 )

dev-infra/pullapprove/cli.ts

@@ -0,0 +1,19 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import * as yargs from 'yargs';
+import {verify} from './verify';
+
+/** Build the parser for the pullapprove commands. */
+export function buildPullapproveParser(localYargs: yargs.Argv) {
+  return localYargs.help().strict().demandCommand().command(
+      'verify', 'Verify the pullapprove config', {}, () => verify());
+}
+
+if (require.main === module) {
+  buildPullapproveParser(yargs).parse();
+}