Stateserver doc initial uuid

Store the uuid of the initial environment in the state server document collection.

The machine ids stored in that document only make sense when linked with an environment.  This seems like the sanest place to store the uuid of the initial environment.

No, this is the environment doc that was added during initialisation.  It has the environment UUID (which we are using here).  For now, and until we have multiple environments, st.Environment() returns the singleton document describing the environment.