Add functions for uploading, listing, and removing OVA images to the API
and CLI interfaces. Includes improved parsing of the OVF and creation of
a system_template and profile for each OVA.
Also modifies some behaviour around profiles, making most components
option at creation to support both profile types (and incomplete
profiles generally).
Implementation part 2/3 - remaining: OVA VM creation
References #71
Add management of the pvcprov database with SQLAlchemy, to allow
seamless management of the database. Add automatic tasks to the postinst
of the API to execute these migrations.
Allow the user to specify other, non-raw files and upload them,
performing a conversion with qemu-img convert and a temporary block
device as a shim (since qemu-img can't use FIFOs).
Also ensures that the target volume exists before proceeding.
Addresses #68
