added user interfaces and utilities that enable experiment data download from machines that have ssh access to the storage host

added DB and DS web service interfaces for deleting user experiment role; added new delete-user-experiment-role command

introduced interface for notifying ds service to update experiment users; fix bug in linux experiment utility

add first functional DS web service with user, experiment and auth controllers that allow retrieving user and experiment information from the db, start/stop experiment, and principal authorization; added corresponding API and CLI classes; added storage manager skeleton