Implement subtitles settings in realtime

**Is your feature request related to a usage problem (not a bug)? Please describe.**
At the moment u have to open the subtitles settings and apply the settings u like for the subtitles. This causes a few problems:

1. The video pauses.
2. If there are no subtitles shown at the moment the video pauses u dont have example text. So that means u will see what settings u applied to the subtitles after u click "Done".

**Describe the solution you'd like to see implemented**
It would look much cleaner if we implemented the subtitles like shown on the screenrecording.

**Describe alternatives you've considered**
None.

**Screenrecording**

https://user-images.githubusercontent.com/73130443/132858515-b0b17567-3fdf-463f-9db1-2e798bdf20fb.mp4

**Additional context**
This would make these issues obsolete https://github.com/FreeTubeApp/FreeTube/issues/1343, https://github.com/FreeTubeApp/FreeTube/issues/968