This is a complete lesson for merge sort which covers the topic merge sort from scratch from its basic introduction to the real world applications.

Fixes Utkarsh1504#74

Short description of what this resolves:

new lesson : Merge Sort

What Changes proposed in this pull request:

-Introduction
-Understanding the merge sort
-implementation + illustration
-code for merge sort
-complexity analysis + stability
-applications

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added code examples, test must pass
• Added documentation so that the program is self-explanatory and educational.
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes: