Embed generator architecture rework

[LTurret]

This module originates from https://github.com/LTurret/Tweets-fetching-module, but it should be enhanced to a dependency due to Arisa's scale.

[LTurret]

Progress Report

The single-picture tweet fix is working as usual 🎉 and we are now moving on to the video fixing tasks.

[LTurret]

Video is uptime, this part of reworks are complete.

[LTurret]

Progress Report

Some of class are not planned because the lack of demand. So, I then focus on other class that used for tweet_subscribtion.

• [x] content_util.py reworked.
• [x] embed_util.py reworked.
• [ ] fetch_tweet.py not plan.
• [ ] get_tokens.py not plan.
• [ ] html_parser.py planed.
• [ ] tweets_segment.py planed.