Moving migration code to new class SQLiteSchema to make managing this easier.

This class is implemented in three .cpp files:

1. SQLiteSchema.cpp - utils and methods to create/migrate
2. SQLiteSchemaMigrations.cpp - existing migrations

I added code comments in SQLiteSchema.h, but if something is unclear, I can clarify.

This code is copied and pasted between places, so there is no need to review the logic itself.

The most important part to review here is native/cpp/CommonCpp/DatabaseManagers/SQLiteSchema.h file.

ENG-10540

Depends on D14572

1. Checkout an older commit and build an app, create an account, and check out to this to make sure migration still works.
2. Log out to check if the database creation works.