This adds the Go template functions from [sprig][] as well as a custom `json`
function that can interpolate any data as a JSON object - very useful for adding
arrays of data in JSON format into a variable:
```
certificateDomains:
- oslo.pub
- tazj.in
annotations:
acme/certificate: {{ .certificateDomains | json }}
annotations:
acme/certificate: ["oslo.pub", "tazj.in"]
```
[sprig]: https://godoc.org/github.com/Masterminds/sprig
Adds a basic CLI structure with a single "run" command that takes a --file (-f)
and --limit (-l) flag.
--limit can be used to only output certain resource sets.
Closes#4
