Add ability to configure leveldb read/write options

:Release Notes:
Add ability to specify leveldb options via configuration file mojodb.conf
Set leveldb  write option "sync" to true

:Detailed Notes:

:Testing Performed:
Compiled and tested localy.

QA Notes:

:Issues Addressed:
[GF-56129] Apply latest leveldb version 1.15 and Change sync option from async to sync

Open-webOS-DCO-1.0-Signed-off-by: Maksym Sditanov <maxim.sditanov@lge.com>

Change-Id: Idab961d6736e2579f58f51cf6be2776368fd46ea
Reviewed-on: https://g2g.palm.com/4243
Reviewed-by: DCO Verification
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Kyouhyun Hwang <kyouhyun.hwang@lge.com>
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>