Donate form doesn't accept comma as decimal seperator
It seems like the donate form does not accept a comma as decimal separator. This is quite unfortunate, as it's the norm in Germany.

In this example I was using the numpad on a german keyboard.
@mal-tee I would like to work on this, can you please guide me through the codebase?
https://github.com/datenanfragen/website/blob/master/src/Components/DonationWidget.js
This is the code for the /donate page. The bug should be hidden here somewhere. Part of fixing a bug is understanding why it's happening. Only then you can fix it.
If you want to know how to get our project running locally, please read the README carefully.
Can you assign this to me?
I have raised a PR, please review it #714