[gaana] Add new extractor

[nikhgupta]

Before submitting a pull request make sure you have:

• At least skimmed through adding new extractor tutorial and youtube-dl coding conventions sections
• Searched the bugtracker for similar pull requests

Found an existing Gaana extractor in #18530 - this PR aims to improve upon that.

• Checked the code with flake8

In order to be accepted and merged into youtube-dl each piece of code must be in public domain or released under Unlicense. Check one of the following options:

• I am the original author of this code and I am willing to release it under Unlicense
• I am not the original author of this code but it is in public domain or released under Unlicense (provide reliable evidence)

What is the purpose of your pull request?

• Bug fix
• Improvement
• New extractor
• New feature

---

There have been several requests for support regarding Gaana.com #12575, #18530, etc. This PR improves upon the code in #18530 by adding valid tests, improving playlist creation, and adheres to youtube-dl conventions as much as I could.

Please, let me know if anything else is required to get this integrated into the core.

[dstftw]

Read coding conventions and fix code.

[SVB-commits]

❤️

[santhosh-v]

Any update on this ?