Store image disk_format and container_format

Store the disk_format and container_format image properties so that the
agent module can pick different image writing utilties based on the
image type that is downloaded

Change-Id: I1f4064a62995ecb8d1202c071f1153ce4e97fc4e
Removed hardcoded IDs from "node" test resources

Test resources are generated using certain helper methods to provide
key/value data. These methods hardcode ID fields which map to primary
key in the database. Subsequent creates on these resources force the
database to assign hardcoded primary keys, ignoring DB's internal
mechanisms. Though unlikely, this could lead to primary key conflicts.

This commit removes hardcoded IDs from node resources.

Change-Id: I29db29516a0a5bb00fa656c96c72636767d24bc6
Partial-Bug: #1268589
Merge "Store image disk_format and container_format"
Merge "Removed hardcoded IDs from "node" test resources"