Filter for YouTube™ live-chats wot TM

The add-on modifies the YouTube live-chat for both live-streams and replay, allowing to either highlight, show as subtitles, or delete chat-messages matching a set of preset and customizable filter rules. This is useful e.g. for showing Hololive live-chat translator messages as subtitles, highlighting English comments, or deleting annoying messages and emoji.

Main features of the add-on:
- Highlighting of YouTube live-chat messages via a separated chat-box
- View live-chat messages as subtitles for YouTube player
- Delete YouTube live-chat messages
- Customizable filter rules, allowing to either enter simple search-texts, or to use more complex options (e.g. Regular Expressions)
- Customizable subtitles style
- Settings are applied to all open YouTube pages and live-chats immediatly
- Light- and Dark-theme support
- Visual design close to YouTube's live-chat and video player design, aiming to not change the look of the YouTube website

Experimental:
- Filter messages regarding characters of languages. E.g. show only YouTube Live-chat messages written with Latin (English) characters.

If there are features or improvements you'd like to suggest, please go to the Support website linked on this Add-On page. I would really appreciate your feedback and ideas for improving this add-on together ^_^.