Convert Python code from "%-formatted" and .format(...) strings into f-strings
Remove existing conversion script that only handles %-formatted strings.
Performance impact:
Before:
$ time arc lint --everything real 2m15,395s user 9m59,264s sys 1m8,720s
After:
$ time arc lint --everything real 2m14,881s user 10m6,171s sys 1m8,421s