[android] Move C++ and core functionality into a separate module

[AndrewShkrob]

Move C++/core into an organicmaps module

Pros:

• Separate UI and core parts of the project
• Having an SDK module that could be used by other apps/developers
• Possibility for development of standalone apps for other platforms like Android Automotive and Wear OS
• Other pros of modules

Cons:

• Huge diff
• Impossible to implement everything under one PR
• Implementing this feature is going to be a long-term project

This is the very first PR that aims to only move the code (and some resources) into a separate module.

[biodranik]

I'm not sure if I got the idea of this refactoring right. Now the code looks more complex, and some new classes were added...

So... what is the main goal(s)? Was it discussed somewhere already? Is it the best way to reach the discussed goals?

[rtsisyk]

What is the goal of this refactoring?

[AndrewShkrob]

What is the goal of this refactoring?

As I already pointed out in the description of the PR, the main goal is to split our source base into core module (sdk) and app module.
I want to add support for Android Automotive which requires a module structure of the project because AAOS app must be a standalone application which is impossible to achieve with the current structure.

[biodranik]

Can AAOS app be started independently, and refactorings/moving of sources be implemented only when required? Focusing now on the SDK structure may complicate things and development.