Updated Evaluator Parameters

This PR is part of the ongoing work to move our named parameters from inner classes to top-level classes, which allows us to use the same parameters in the JVM and .NET implementation of REEF:

  * Moved all inner classes in `EvaluatorConfiguration`  to the package `com.microsoft.reef.runtime.common.evaluator.parameters`
  * Renamed `EvaluatorConfigurationModule` to `EvaluatorConfiguration` to bring it in line with the other uses of ConfigurationModules in REEF.