[web-db] process Draft Store Operations on worker

Summary:
Processing available draft store operations on SQLite database via worker.

Depends on D7124

Test Plan:
Run this code

await webDBWorker.scheduleOnWorker({
   type: workerRequestMessageTypes.PROCESS_STORE_OPERATIONS,
   storeOperations: { draftStoreOperations }

});

in web reducer and check if operations are properly processed

Reviewers: michal, tomek, marcin, ashoat

Reviewed By: ashoat

Subscribers: ashoat, atul

Differential Revision: https://phab.comm.dev/D7153