REIVEW: [NX-518] Orient database manager

This PR addresses the following issues:

https://issues.sonatype.org/browse/NX-518
https://issues.sonatype.org/browse/NX-519
https://issues.sonatype.org/browse/NX-542
yes, though as mentioned above I deferred this for now, as I think we'll want a bit more smarts in this at some time in the future to expose shared pools, etc.