Previously, we had only set __webpack_public_path__ to a path which
caused webpack chunks to be loaded from the current origin which is
incorrect when STATIC_URL_PREFIX points to another origin.

This should fix the issue curretnly seen on gitea.com.

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lauris BH <lauris@nix.lv>

* Remove IE11 support

With master now on 1.13, it's time to drop IE11 for good. The woff
variants are also in use by Opera Mini but it has even less market share
and I can only imagine how broken the UI is in it.

Fixes: https://github.com/go-gitea/gitea/issues/6147

* update docs

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

- lowercase all js filenames except Vue components
- enable new lint rules, mostly focused on shorter code
- autofix new lint violations
- apply misc transformations indexOf -> includes and onevent-> addEventListener

Co-authored-by: Antoine GIRARD <sapk@users.noreply.github.com>

This changes the CSS output of webpack to output to the public/css
directory instead of inling CSS in JS. This enables CSS minification and
autoprefixer based on browserslist which would otherwise not be
possible.

The result of this change is two new output files currently:

- public/css/swagger.css
- public/css/gitgraph.css

Co-authored-by: techknowlogick <matti@mdranta.net>

- moved gitgraph.js to web_src and made it importable and es6-compatible
- created new webpack chunk for gitgraph
- enabled CSS loader in webpack
- enabled async/await syntax via regenerator-runtime
- added script to ensure webpack chunks are loaded correctly
- disable terser's comment extraction to prevent .LICENCE files

gitgraph.js has many issues:

1. it is incompatible with ES6 because of strict-mode violations
1. it does not export anything
1. it's css has weird styles like for `body`
1. it is not available on npm

I fixed points 1-3 in our version so it's now loadable in webpack. We should eventually consider alternatives.