feat: add playground application to run the SDK

[frederikprijck]

Changes

Adds a very basic playground application to test the SDK manually when needed.

Checklist

• [x] I have read the Auth0 general contribution guidelines
• [x] I have read the Auth0 Code of Conduct
• [x] All existing and new tests complete without errors

[semgrep-app[bot]]

Semgrep found 1 ssc-1286f396-f1d3-46c6-9e68-74429d10c3c4 finding:

• yarn.lock: L5494-5495

Risk: vm2 versions before 3.9.15 are vulnerable to Improper Control Of Dynamically-Managed Code Resources due to improper control of dynamically-managed code resources related to Error.prepareStackTrace in unhandled async errors. A threat actor can bypass the sandbox protections to gain remote code execution rights on the host running the sandbox.

Fix: Upgrade this library to at least version 3.9.15 at node-auth0/yarn.lock:5494.

Reference(s): https://github.com/advisories/GHSA-7jxr-cg7f-gpgv, CVE-2023-29017

_{Created by ssc-1286f396-f1d3-46c6-9e68-74429d10c3c4.}