Duration picker rework

[xal]

Fedi uses forked(simple hacks for Fedi) version of duration_picker without adopting picker to the current locale. Possible solutions:

• refactor duration_picker fork and publish PR and use the updated library
• fully rework picker and remove duration_picker dependency
• unify UI elements with #78

[xal]

https://github.com/juliansteenbakker/duration_picker/pull/6