Check cargo sort in make check

[naseschwarz]

This is run in CI, so running this offline avoids an unnecessary CI failure.

This Pull Request fixes/closes #{issue_num}.

It changes the following:

• Adds a make sort target, which runs cargo sort
• Runs make sort also for make check

I followed the checklist:

• I added unittests
• I ran make check without errors
• I tested the overall application
• I added an appropriate item to the changelog

[extrawurst]

lgtm, surprised it was not in there yet