1. Prepare Pure and Bell specific `Application`
classes and add them to `app` target:
- `products/BellHybrid/apps/Application.cpp`
- `products/PurePhone/apps/Application.cpp`
2. Update `CMakeLists.txt` files.
3. Move `ApplicationBell` implementation to Bell-specific
`Application` class and remove `ApplicationBell` files.
4. Change Bell apps parent classes from `ApplicationBell`
to Bell-specific `Application` class.
5. Rename `Application` to `ApplicationCommon` in the rest of the files.
According to PurePhone design emergency call
window is needed after "SOS" callback at the screen lock.
This PR introduce implementation of emergency call window
and also refactor in the enter number window. Both windows
derives from new number window.