cruiseCommandExecutor: configure the container with a singleton storagemodel
fileSystem: add fileExists() method
storageController: check the config file exists before reading
commandExecutor: dont save the config on each run
tests: remove unused base class
commandExecutor: move container outside the executor
container: extract configuration to a registry
cruise: rework how the commandFactory is built for better testing
tests: use new commandFactoryBuilder, and check command return type properly
storageModel: use a memento for storing
reponse: add a response writer
storageModel: add methods for registering new servers