Add subtitle mode (videoplayer-like displaying), fix parsing SRT and refactor

[FeniXb3]

I found this repository while looking for subtitles plugin for my accessibility workshop. I liked that you use SRT format, as I was looking for something that could be used in cutscenes. However, I realized that it's not using the data as videoplayers do and instead of creating my own version from scratch I decided do build on top of your project and give my changes back.

It started small, but in the end git diff will not be useful to finding out what the changes are. So, to sum up in few points:

1. Code was refactored - I've seen some redundant parts and started to limit repetitions whenever I knew what to do.
2. Static types were added in most places - it made it easier for me to know if everything was working well, as I had more code completion.
3. Some issues were fixed - SRT might have multiple lines in each segment and it was not working correctly. Regex used can be tested here - https://regex101.com/r/MCt4cQ/1 It's based on this SO answer - https://stackoverflow.com/a/71585341/1816426
4. "Subtitles" mode was added - that's the only thing I needed and I believe more people might be interested in it.
5. Getting parsed captions/subtitles only was separated - in my opinion it's better than having the "TimeOnly" parameter.
6. Return types of functions were unified - some functions were either returning Animation or bool or Dictionary.

Feel free to take whatever you feel fitting. I know it's a lot for a single PR, but I didn't want to create multiple PRs with different changes, as most parts were interconnected due to refactor. You can check separate commits I did to see how it progressed.

There are some parts I would change even more but I have to move on with the workshop and leave reafactoring for now.

[FeniXb3]

Oh, and I forgot I wanted to attach a video, showing the "Subtitles" style:

2024-03-25.16-45-40.mp4