These will soon take over ESLint and stylelint, plus they also cover
ruff and other goodies for the Python part. This supersedes the explicit
ruff call.
This is already being used by cockpit-{podman,machines,navigator} etc.
Apply our standard set of rules from our cockpit projects, and fix some
minor fallout:
```
test/check-application:7:1: I001 [*] Import block is un-sorted or un-formatted
test/check-application:9:119: E501 Line too long (122 > 118 characters)
```
Run ruff in CI to ensure we don't break it.
run-tests recently got a new `--track-naughties` option [1] to explicitly
enable updating known issues on GitHub. Enable it for CI runs, and leave
it disabled for local runs and PackIt, as in these cases we don't want
to try and talk to GitHub.
[1] 7ef88e80ce
Similar to what cockpit-composer does. This is rather simplistic, but
does fine until we need more complex scenarios.
Also use plain shell in test/run, there are no bashisms.
Closes#291
