Fork sisyphus and maintain

[hansegucker]

While implementing #1575, I discovered that sisyphus is broken and isn't maintained since seven years. As the source code is only 550 lines long and we could save some more lines by dropping unnecessary stuff, I would suggest to take the source code, drop the jQuery dependency and maintain it as .ts file in our source.

[hansegucker]

@richardebeling @niklasmohrin @Kakadus Would be great to get an opinion.

[richardebeling]

Generally open to it, but I'm afraid without jquery it would be a bit more code -- if there's a way where we don't add more maintenance overhead, I'd prefer that :D

How is it broken -- anything we need to fix?

[niklasmohrin]

I think it would be nice to have it in our repo for up to 200, maybe 300 lines of code. The original code has lengthy comments and support for some weird editor, I feel that it should be doable with modern browser APIs and typescript features in ~200 lines.