Code cleanup

ReplicationCliMain.java:
Used static import for ADSContext.
Removed promptIfRequired(PreExternalInitializationUserData) and promptIfRequired(PostExternalInitializationUserData), and replaced them with promptIfRequiredForPreOrPost(MonoServerReplicationUserData).
Extracted initialize(ReplicationUserData) to factorize code.
Removed several initializeWithArgParser(*UserData) methods and replaced them with a initializeWithArgParser(MonoServerReplicationUserData).
Extracted methods toString(Throwable), newBooleanArgument(), findArg(), existsArg(), addArgument(), getBindPassword1Arg(), getBindPassword2Arg(), getBindPasswordFile1Arg(), getBindPasswordFile2Arg(), getBindDN1Arg(), getBindDN2Arg(), getAdminPasswordArg(), getAdminPasswordFileArg(), getHostArg().