Calculate rarity from JSON file

[fekete965]

Prerequisites

Please answer the following questions for yourself before submitting an issue.

• This is a feature request only 💡
• I am running the latest version
• I checked the documentation
• I checked to make sure that this feature has NOT already been requested

Why are you requesting this feature
It would be beneficial if the application could process local files:

1. It would make the application more versatile, offline work would be supported
2. Debugging calculations would be more straightforward (anybody could share their data and that data can be easily tested/processed by anybody to help find any issue)
3. Testing the calculations would be finally possible (we can you mocked data)

Describe the solution you'd like
Additional menu where we could select a JSON data from within the application's folder for processing

[fekete965]

I'd be very happy to work on this feature. :)

[0xSooki]

Amazing idea @fekete965 feel free to work on it :)