[Identity] Write a troubleshooting guide and link it through the docs

[sadasant]

Let’s start writing a troubleshooting guide for JavaScript, and let’s make sure it’s properly linked.

Here are some tips we should take in consideration when writing this guide:

• Go through the past Identity issues on JavaScript, write down the common responses and other patterns, use them to include content in the troubleshooting guidelines.
• Go through MSAL’s docs and issues and repeat the process.
• Take in consideration this troubleshooting guideline proposal for Java: Add Identity Troubleshoot doc and logging updates  azure-sdk-for-java#23502 but make sure to use it as a reference after Scott Addie has reviewed it, and his feedback has been addressed.