* added `showEV100` to user preferences
* integrated EV100 setting to UI
* available for pro
* replaced `IAPProducts.isPurchased` with context extension
* fixed `UserPreferencesProvider` tests
* EV100 -> Ev100
- Fixed test coverage calculation
- Removed `mockito` from the application mock
- Implemented platform channel mocks to mimic incident light metering
- Covered providers with unit tests
- Covered metering screen pickers with widget tests
- Laid foundation for integration tests