[FEATURE] Extended CurrencyRepository. Added methods to fetch currencies

__Tasks:__
- [x] done
- [x] got feedback

__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Tests pass?   | none
| Fixed tickets | none
| Doc           | none

__Requires:__

wrong variable naming: should be NOT changed