Use unlogged batches instead of atomic batches

MagnetoDB API doesn't require atomic batches
so we can improve performance by using unlogged batches

Implements: bp improve-batch-write-performance

Change-Id: I139358ad6424095243f36b7f2a619ed0243ecdfe
Add queued storage manager

Change-Id: Ibcb05258f2644fac46c783f46429c0761f802744
Implements: async-shema-operations