Add scanner support to accept deposit return vouchers (Apps-1642)

[Fabtron]

Deposit return vouchers can now be scanned. This means their accepted and a matching line item is added to the shopping cart.

This story does not contain violation handling or ui parts.

APPS-1642

How to test?

Integrate this branch into an app usinng deposit return vouchers and scan it. On Success the default scanner message with added appears and the price automatically updates.

Definition of Done

• Issue is linked
• All requirements of the issue are fulfilled
• Changelog is updated
• Documentation is updated
• Self-Review
• Review with the Product Owner (Release-Variante o. Minified Build)

App Tests

• Minified build has been tested (aka. Release Build)
• Environments have been taken care of (Production/Staging)
• Supported languages have been tested
• Light-/Dark-Mode has been tested
• Edge-Cases have been tested
• Android API Levels have been taken care of (minSdk?)

Testing

• Tests have been written (aka Unit-Tests, Integration-Tests, ...)