[RocksJava] Integrated code review comments

- Added TODO comments for disabled methods
[RocksJava] Extend Options with DBOptions implementation [RocksJava] Included DBOptionsTest and refactored OptionsTest

Summary: Options refactoring - Split Part2

Test Plan:
make rocksdbjava
make jtest

Reviewers: yhchiang, ankgup87

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D28017