add a basic RESTful API for users
add cellar API
extend datastoreRest(Put|Get) to return http status and error

This allows these functions to stop writing JSON which simplifies the
call stack and test code.
drop (get|put)AdminConfig()

These functions weren't providing any value.
inline datastoreRestPut()
refactor getters as methdos with receivers; reuse them elsewhere
brevity
add beer API