k8s tools docker image

[bmonkman]

We often find it useful to have a docker image to assist in debugging inside a k8s cluster, it should include tools like:

• curl
• siege
• mysql and postgres clients
• ~a reverse proxy to allow us to pass traffic through to an internal service like a database using kubectl~
• tcpdump
• etc.

[sshi100]

add them into zero-k8s-utilities