KNOX-476 implementation for X-Forwarded-* headers support and population

KNOX-546 Consuming intermediate response during kerberos request dispatching

KNOX-550 reverting back to original hive kerberos dispatch behavior

KNOX-559 renaming service definition files

KNOX-561 Allow Knox pid directory to be configured via the knox-env.sh file

KNOX-545 Simplify Keystore Management for Cluster Scaleout