[vimeo] Add support for VHX subscriptions

[stanciuadrian]

IMPORTANT: PRs without the template will be CLOSED

Description of your pull request and other information

Adds support for https://embed.vhx.tv/subscriptions/ URLs.

Based on the https://embed.vhx.tv/videos/ extractor.
The URL needs the vimeo=1 parameter to work.

Fixes #4560

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 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?

• 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 tests

[stanciuadrian]

These are mostly paid-for videos.
I'll try to find an example that doesn't require a cookies.txt file.

[pukkandan]

Even so, you can still add a test and run it yourself. Once you have ensured the test passes, add 'skip': 'Needs authenticated cookies' to skip it from automated testing