css-loader@4 broke @import statements referencing files with
extensions other than .css, unless those @import statements are
compiled away by another loader. Upstream is more interested in
arguing that such @import statements are semantically incorrect than
applying the one line fix.
https://github.com/webpack-contrib/css-loader/issues/1164
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This commit transitions all styles in app.css in the Django pipeline
to being compiled by webpack in an app-styles bundle, and renames the
various files to now be processed as SCSS.
To implement this transition, we move the old CSS file refernces in
settings.py and replace them with a bundle declared in
`webpack.assets.json` and includedn in the index.html template
Tweaked by tabbott to keep the list of files in `app.css` in
`webpack.assets.json`, and to preserve the ordering from the old
`settings.py`.