[mp4upload] Add new extractor

[ghost]

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• At least skimmed through adding new extractor tutorial and youtube-dl coding conventions sections
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What is the purpose of your pull request?

• Bug fix
• Improvement
• New extractor
• New feature

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Description of your pull request and other information

Added Mp4Upload support, which offers Anime, gaming videos. Known sources where you can get MP4upload embeded links exist like MasterAnime. Was included in one of my android apps as java, but I ported it to python because I thought it deserved to belong here in youtube-dl as well.

[ghost]

Ah crap, didn't notice it, well the other one seems inactive and has better code.. Maybe we should focus on it again