Port base object from Nova.

Forked from Nova ed6099d77ed1ee4a2c8c8b135d6ac18f70d48625 and
pulled 'deleted' attribute from Nova 15fe833f5fb8d847a21061d802d194a74cf3d0ad.

Resolved dependencies and renamed all "Nova-" to "Ironic-"
The patch implements: blueprint db-objects

Change-Id: Id51599af88fe84451b3e746a9e51bd760d61da84
Merge "Port base object from Nova."