Adding Mesa Extension page

[PrashantChoudhary13579]

Summary

This PR adds a Mesa Extensions Overview page to the mesa inside the docs folder. This page contains the basic extensions like - Mesa-Geo, Mesa Examples, Mesa-Frames up to this point. Each of them contains the description, Key feature, Authors, each one GitHub link in more information, etc...

Motive

• There should be a page which contains Mesa's Extensions making the new users easier to get an overview of the extensions used in the mesa.
• To solve the " Docs: Create overview page of extensions #2190 " issue

Implementation

• Added a page which contains Mesa Extension containing - Mesa-Geo, Mesa-frames, Mesa-Example
• Each of them contains Description, Key feature, Author, GitHub link, etc.
• This is done by going through each of the repository and extracting out the data and concising them into the file accoring to the above format

Usage Examples

The page will be generated after executing the make html command in the terminal or building the source code of docs folder.

Additional Notes

• Docs: Create overview page of extensions #2190 contains some of my doubts