Add RTVE Play

[joaquinito2070]

IMPORTANT: PRs without the template will be CLOSED

Description of your pull request and other information

Adds Rtve Play

Fixes #

Template

Before submitting a pull request make sure you have:

• [x] At least skimmed through contributing guidelines including yt-dlp coding conventions
• [x] Searched the bugtracker for similar pull requests
• [x] Checked the code with flake8 and ran relevant tests

In order to be accepted and merged into yt-dlp 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
• [x] 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?

• [x] Fix or improvement to an extractor (Make sure to add/update tests)
• [ ] New extractor (Piracy websites will not be accepted)
• [ ] Core bug fix/improvement
• [ ] New feature (It is strongly recommended to open an issue first)

[pukkandan]

Add a test

[pukkandan]

• The old URLs still play in browser and must remain supported.
• Similarly, atleast one of the old tests should be kept.
• You obviously haven't actually run the tests!
• Do not rename the extractor. IE_NAME/DESC can be changed though

[dirkf]

See https://github.com/ytdl-org/youtube-dl/pull/31241.