fix: "5 minutes" translation and fine tuning strings

[buhtz]

• Improved some translatable strings and fixed problems encountered while watching the ongoing translation process of our translation team. The intention about moving from printf()-style string formatting to Advanced String Formatting (PEP 3101) or f-string formatting (PEP 498) is to make our strings easier to understand by translators who are not (Python)-Developers. It also reduce the amount of string-format-errors introduced by translators.
• Fix a translation related minor bug (reported via comment on commit by @Fantu)
• Workaround Weblate Issue #9449 misinterpreting not escaped %. The % don't need to be escaped when using Advanced String Formatting but Weblate isn't able yet to differentiate the multiple string-formatting styles in its check routines.