Patch localforage to support transactional multiple items retrieval/persistence

Summary: This differential patches localforage to support transactional multiple item retrieval/persistence. The synchronizationKey and synchronizationValue arguments are used to handle race conditions. setMultipleItems will only succeed if current value under synchronizationKey in localforage is equal to expectedSynchronizationValue or forceWrite is set to true. This lets us select on thread to always win race condition.

Test Plan: tested with next diff

Reviewers: kamil, tomek, inka

Reviewed By: kamil

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D12836