Add sbs.co.kr extractor

[seproDev]

IMPORTANT: PRs without the template will be CLOSED

Description of your pull request and other information

Added extractor for SBS a Korean TV network.
I don't like the class names, but couldn't come up with anything better.

Template

Before submitting a pull request make sure you have:

• At least skimmed through contributing guidelines including yt-dlp coding conventions
• Searched the bugtracker for similar pull requests
• 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 all of the following options that apply:

• 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?

• 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)

Copilot Summary

🤖 Generated by Copilot at acae621

Summary

🇰🇷🎥🆕

This pull request adds support for extracting videos from the South Korean broadcaster SBS's websites, such as allvod.sbs.co.kr and programs.sbs.co.kr. It introduces a new module sbscokr.py that defines three new extractor classes, and imports them in _extractors.py.

SBSCoKrIE class
Extracts videos from SBS
Winter entertainment

Walkthrough

• Add support for extracting videos from SBS websites (link, link)
  • Import the classes SBSCoKrIE, SBSCoKrAllvodProgramIE, and SBSCoKrProgramsVodIE from the module sbscokr.py in _extractors.py (link)
  • Define the classes SBSCoKrIE, SBSCoKrAllvodProgramIE, and SBSCoKrProgramsVodIE in sbscokr.py (link)