[extractor/facebook] improve metadata extraction

[ghost]

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Description of your pull request and other information

Resolves # 29421, resolves # 23627, resolves # 23180

Improve title, add description. Prefer metadata in JSON-LD if present.

This PR doesn't touch playlists. Some tests (mostly of playlists) remain fail, and may need other PRs.
TestDownload.test_Facebook_7, 9, 10 (playlists)
TestDownload.test_Facebook_14 (get ERROR: Cannot parse data)