docs: add an in-depth RNTL guide link to the Getting Started page

[anisurrahman072]

Summary

• Added a link of RNTL in depth guide to the Getting Started page Example section

• The Guide link that was added, got huge response from community (800+ GitHub STAR in a repo where the Guide was added & ~400 CLAP from Medium devs)

• The Guide covered 👇

      1. Almost all the parts of RNTL in most easiest way
      2. Almost all types of JEST config for RNTL with examples
      3. All types of Mocking by RNTL
      4. Common errors of Jest configs & their solutions
      5. Many more with proper examples & guide
  

• RNTL Discussion Link: Published an In depth Guide on RNTL (700+ GitHub STAR & ~400 CLAP in Medium) #1555

• RNTL Guide Link: https://github.com/anisurrahman072/React-Native-Advanced-Guide/blob/master/Testing/RNTL-Component-Testing-ultimate-guide.md

Test plan

• Please review changed content
• Also, please check the RNTL in depth guide, as it can benefit the CallStack community.

Change to the Guide

• I’m eager to accept any suggestions to modify the guide so that it can help the CallStack community.

[mdjastrzebski]

@anisurrahman072 congratulations on your success! I have heard about your guide before. Allows us to check it out before we merge this PR. This might take couple of days, as the guide is quite long and I have limited time due to other obligations.

[anisurrahman072]

Sure @mdjastrzebski ✅

Please take your time. Also, if you feel anything that should be updated in the RNTL guide, please let me know. I will do that sure 💯

[mdjastrzebski]

Docs updated in #1558.

@anisurrahman072 thank you for contributing your comprehensive guide to the benefit of the whole community! ❤️