FR: Set default / change default currency

[Silther]

Is your feature request related to a problem? Maybe it would be better as discussion? Please describe.
With the addition of currency conversion it is now easier than ever to have multiple currencies, and currently you have to specify each of them for every balance.

Describe the solution you'd like
Would be nice if you can specify your default currency, and every balance would auto converted into that, maybe groups could have there own default currency.
In addition you should be able to modify your currency in the settings the same way you can change your language

Describe alternatives you've considered
it's only a convenience feature as every currency can be change by hand already.

App version
v2.0.0

Additional context
...

[krokosik]

Yes, that would be a nice addition. Due to the amount of work for v2 I saved it for later, but definitely see something like that being added, but a refactor to user details and group settings is badly needed beforehand.