TACHYON-198 Move UserConf usage to use TachyonConf

This PR consist next steps to integrate new configuration work:
-) Remove usage of UserConf
-) Push TachyonConf to Tachyon Hadoop's file system (aka TFS class).
-) Remove UserConf.java from repo.
The primary use is for merging TachyonConf from hadoop job request in the Tachyon Hadoop file system.
Other uses for now is in local cluster test to set conf for both mastr and worker conf.