[enhancement] Optionally show secondary subtitles as selectable text rather than an image

[AuroraWright]

Hi, thanks for your work, I'm glad we still have a working foss option!
I have a suggestion I think would be welcomed by a lot of Japanese learners. I noticed that currently the addon is turning the secondary subs into a svg image it then overlays on the window. Yomichan/Yomitan is a pretty popular extension in the Japanese learning community that allows you to quickly look up words and add them to Anki for further studying, by just hovering over them. (e.g.:

It would be nice if there was an option to display the text as a textbox or something like that, to make this work (I think there's an extension already, but it's not foss and subscription based).
Thanks again!