Implements blueprint per-user-quotas.
Based on the original quotas structure.
NOTE:
quota_instances, quota_cores, quota_ram, quota_volumes,
quota_gigabytes, quota_key_pairs and quota_security_groups
are supported per user.
Allow 'projectadmin' role to access the user quota setting
methods.
Add commands 'nova-manage quota project/user' for quotas
management.
Change-Id: I07a39499432571fedd819c53ae414240cefc3354