Summary:
This takes the questions currently on the front of the Wordpress-based rocksdb.org and starts an official FAQ with them.
Depends on: https://reviews.facebook.net/D63105
Test Plan: Visual
Reviewers: IslamAbdelRahman, lgalanis
Reviewed By: lgalanis
Subscribers: andrewkr, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D63123
