* Introduces flow types for storage
* Better typing of QueryOptions
* Adds flow types to SchemaCOntroller,
- runs flow on pre tests
- fixes flow
* Adds ClassLevelPermissions type
* Moves Controller types into a single file
* Changes import styles
* Changes import styles
* fixing method setIndexesWithSchemaFormat (#4454)
Fixing invalid database code in method `setIndexesWithSchemaFormat`:
* It must be a transaction, not a task, as it executes multiple database changes
* It should contain the initial queries inside the transaction, providing the context, not outside it;
* Replaced the code with the ES6 Generator notation
* Removing the use of batch, as the value of the result promise is irrelevant, only success/failure that matters
* nits
* Fixes tests, improves flow typing
