Date strings would output month names always in English.
Now the chrono unstable-locales feature is used to localize the date string. Redundant formatting code was moved into utils.
Closes #251
Waiting for feedback on: #251 (comment 1382447) then I'll remove the draft status.
In a second commit I also moved the duration formatting code to utils and fixed some panic crashes when the episode duration is above 24h.