dataengines/weather/dwd: Fix searching places with umlauts

Reason for the change

The station list where the provider searches from does not contain the place's names with umlauts, so transform the user search text in order to find them.

The station list for reference

Test plan

Search for würzburg location. Without this patch you'll get the subpar wetter.com option, because the Deutsche Wetterdienst one is not found

Screenshots or screen recordings

Before	After

Bugs fixed

Fix of utmost importance for the upcoming Akademy!
We want to give our contributors the best option available

Pinging someone local 😄