[TACHYON-8][TACHYON-194] Move some MasterConf and CommonConf usages to use TachyonConf

This PR contains changes to push instance of TachyonConf to some of the components such as Master and Worker to replace usages of CommonConf and MasterConf.

The PR passes all unit tests so it is a good indication how the rest of code will change to use TachyonConf instance instead of static calls to xxxConf.get().

This PR should give sample on how to use TachyonConf to process the properties configuration.
Why is this logic in the conf class? TachyonConf shouldn't know about any specific properties and shouldn't have custom logic.