Summary:
This patch introduces OptionsSanityCheckLevel internally to enable
sanity check rocksdb options.
Utilities API will be added in the follow-up diffs.
Test Plan: Added more tests in options_test
Reviewers: igor, IslamAbdelRahman, sdong, anthony
Reviewed By: anthony
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D49515
