Currently the PR becomes successful-green as soon as CI fully passes
but before it's merged, which can be an issue as e.g. merging might be
delayed (there's no visible difference between "CI success" and
"staging merged") or it might ultimately failed (FF error).
Create an intermediate color for "successful" stagings which are still
pending merge.
Also add a fallback message for fast-forward errors instead of en
empty string.
Closes#308
bs4 yields complete vomit on the template as-is (see:
https://imgur.com/a/XIMn7MX).
Add a bunch of color and styling overrides to get something closer to
the original, and move the existing styles to a "proper" scss file
while at it.