Remove management-staging and management-staging-egress spaces

[neilmb]

We aren't deploying our broker in the management-staging space any longer and so these two cloud.gov spaces are extraneous and we should delete them.

[rshewitt]

logstash & space drains apps are in management-staging and are used by staging apps. there's no apps in management-staging-egress but the idea would be to create the logstash & space drains for proxies. since that hasn't been done already then maybe we can delete that space?