Add initial migration and participant adding/editing

This adds participant adding and editing, in the "Manage Participants" section. Also includes the initial db migration.
Remember - the cohort is established by the pregenerated Participant Id. I think that location was meant to determine the current session, e.g. Facilitator logs in 8 participants at given time/place. The "session" is established via those three attributes - who logged the user in, the time and place. I think you had stubbed out the sense of a Session previously and I questioned it...perhaps this is actually the information that needs to be stored a Session object. FacilitatorId, ParticipantId, Location,Created.