Create MongoDB tenant datastore type with pluggable event storage
Create a new MongoDB tenant datastore component that allows the underlying device event storage to be plugged in. This will allow MongoDB to used for device management and asset management, but push event storage into HBase, InfluxDB, or other providers.
After SITEWHERE-258, this is accomplished by configuration rather than coding. Since event management is now totally separate, any combination of device management and event management implementations can be assembled via Spring.