Addresses #75

Adds optional bulk read of subnets through ports. Fixes the previous
patch by allowing network_id and tenant_id to always be shown,
regardless of fields passed.
Merge pull request #135 from Cerberus98/port_load_subnets_squash

Addresses #75
Allows manual reset of deallocate_at for admins

Done through PUT to /ip_addresses with "reset_allocation_time": true in the
body.

A few modifications were done to base_tests to support the admin context.

Had to prevent admin_roles from being loaded on context.

Removed the DEFAULT_ROUTE thing for great justice!

Non-admin access will raise HTTPForbidden.

RM6300