Allow environment to reference instance(s) from different environment(s)

A user should be able to reference other environments. If there is an add-on (monitoring, configuration management, etc) to an application, only one server should be deployed for the tenant. Each environment in the tenant should be able to find and reference the environment where the server is defined.

For instance a Puppet Master or Zabbix Server is created for the tenant. When an environment is created, the user should be able to add a puppet slave or zabbix agent to the environment. The slave/agent is added to each application in that environment and needs to be able to reference the puppet master or zabbix server for information (certs, users, passwords, etc).