Added Counting Sort in Python

[rupeshkumar22]

Description

Documented Example in file

Fixes #549

Type of change

Please delete options that are not relevant

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] This change requires a documentation update

Checklist:

• [x] I have read the contribution guidelines before making this PR.
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented in my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation (Language folder or any other readme instructed to)
• [x] My changes generates no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works

[rupeshkumar22]

Okay

[rupeshkumar22]

Please review the change @kaustubhgupta