Support CNI + IP per container

[frankscholten]

Currently Marathon and Mesos expect containers to use the host network stack. Minimesos however runs in containers and uses separate network stacks which causes #401.

Let's support IP per container http://mesos.apache.org/documentation/latest/networking-for-mesos-managed-containers and http://mesos.apache.org/documentation/latest/networking-for-mesos-managed-containers to solve this.

[frankscholten]

CNI Support + host local plugin

To keep things simple let's focus first on enabling CNI and configure the host-local IP address manager (IPAM). Once that works we can support more complex technologies.

TODO

• Add CNI config + host-local plugin to the Mesos Agent image
• Release Mesos Agent image to Docker Hub
• Update the Mesos Agent image version in minimesos config
• Add an example app in the default Marathon file that demonstrates IP per task functionality