feat: Add 2nd-gen YouTube sample to Node folder

This commit introduces a new 2nd-gen Cloud Function sample for YouTube, located in the `Node/youtube` directory. This sample is the TypeScript equivalent of the existing 1st-gen sample in `Node-1st-gen/youtube`.

Key features of this new sample include:
- Use of 2nd-gen Cloud Functions.
- Written in TypeScript, leveraging Node 22's optional type stripping.
- Implements a secret parameter for the YouTube API key, enhancing security.
- Provides a clear and updated README.md with instructions for setup and deployment.

Author: google-labs-jules[bot]

Node/youtube/functions/index.ts

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-const { onCall } = require("firebase-functions/v2/https");
-const { defineSecret } = require("firebase-functions/v2/params");
+const { onCall } = require("firebase-functions/https");
+const { defineSecret } = require("firebase-functions/params");
 const { google } = require("googleapis");
 
 const youtubeApiKey = defineSecret("YOUTUBE_API_KEY");