TemplateConfig implementation with Kubernetes

Initial implementation of TemplateConfig REST endpoint.

See the project.json example.

To test this PR:

```
$ curl -d @pkg/template/examples/project.json \
  http://localhost:8080/api/v1beta1/templateConfigs
```

This will return `Config{}` which is essentially the same as a `templateConfig{}` but without parameters.

**FYI**: This is a wip, all commits will be squashed in the end. @VojtechVitek is working on validation atm. so I don't want to force push ;-)
@bparees I understand how `json.Unmarshall()` parses:
- `{"service": {..ServiceData..}, "pod": {..PodData..}}`

but I don't understand how it parses
- `{"items": [ {"kind": "Service", ..ServiceData..}, {"kind": "Pod", ..PodData..},..] }`