Enhancement: Improve slider handling for amounts

[DGrothe-PhD]

Summary

As a user, I might take an occasional 5-km ride or buy some 100 or 125 grams of chocolate, etc.
However, I currently observe that

• the closest to those 100 grams of chocolate is 97g, 113 g or something of that kind
• Fun fact on the other hand: I was able to jot down exactly 20 grams of red meat that seems to work better but I don't know why.
  So far I cannot figure out what dictates these ticks after all …
• the smallest distance I can enter by sliding is 2 km for a ride, next tick appears to be at 55 km
• and with further practice, I might be lucky to add 17 km, again far from the 5 km I was trying to enter.

Proposed feature

• The slider for entering metric amounts should have some more practical ticks and/or
• Preferredly: Being able to tap on the number above the slide and this opens a (standard) keyboard for entering a number.

Maybe such a number field is standard one with some accessibility improvement for some challenged people

To Do List

• Code
• Tests
• README.md updated

[PierreBresson]

@DGrothe-PhD : thanks for the feedback, that's correct, it's not handy, so I've designed a solution for this problem. You can find the proposal here. Feel free to add anything feedback on the issue with you find something in the design that could be improved, I will update the design in figma ;)