Implemented as part of ENG-10603.

Currently, we have:

1. SQLiteConnectionManager that is used on the web
2. NativeSQLiteConnectionManager that is inheriting from the class SQLiteConnectionManager and overrides a couple of methods to be native-specific.
3. SQLiteQueryExecutor that owns *connectionManager and uses it, but connection management is implemented in multiple places.

This diff changes the approach to the following:

1. SQLiteConnectionManager will be an abstract class with pure virtual functions that depend on the platform (this way, we can avoid directives in SQLiteQueryExecutor and put platform-specific implementation into dedicated classes). Shared code will be implemented in this, parent class
2. NativeSQLiteConnectionManager that is inheriting from the class SQLiteConnectionManager and overrides native-specific methods.
3. WebSQLiteConnectionManager that is inheriting from the class SQLiteConnectionManager and overrides web-specific methods.
4. SQLiteQueryExecutor that owns *connectionManager instance based on platform, but connection management will be fully moved to *connectionManager (later in the stack)

Depends on D14573

Login/logout on web