make compatible with chromium 83

[hawken93]

Chromium likes to pass event data json encoded, so I made a check to deal with that.
Also 2 BOM removals

[YouKnowBlom]

I thought all images were included by html-webpack-plugin but I see now that I missed a few, good catch :p. I think we should try to make use of the css-loader plugin as that parses url()s by default

https://webpack.js.org/loaders/css-loader/#url

[hawken93]

I've messed around some more and made it work the way you wanted I think. But please check for yourself too. I also noticed favicon didn't have anything to help it. Keeping in mind that it needs to retain its filename I just copied it over. Without the copy plugin, webpack seemed to ignore it.

[hawken93]

I've added some comments to make it easy to understand my intention with every change

[hawken93]

Looks like it messes up production mode..

[hawken93]

I've reverted back to my copy approach after css-loader introduced more mess than I was able to fix. I also discovered fonts were being left out, so I've fixed that too. Apparently it's not enough to define handlers for the file extensions, they need to be referenced too in a way that webpack understands. css-loader would fix that but it refuses the current index.html way of including them normally. the CSS files can be added as entrypoints, required from app.ts or in index.html they can maybe be referenced like <style>css/jellyfin.css</style>. When referenced in index.html they are inlined because reasons.

[hawken93]

If anyone can make it work with css-loader, please open a separate PR and merge that, then I'll make corresponding changes here. :)

[hawken93]

Recommend solving the webpack stuff here:
#88

I'll make this PR only about the chromium workaround following merging that one :)

[YouKnowBlom]

Converting this to a draft until #88 is ready :p

[hawken93]

rebased on top of webpack-fix PR, this PR will get much cleaner after that one is merged :)

[hawken93]

Updated title and description to match the content of the pr