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 ;-)
well, if you think about this more, we can also do substitutions in properties like 'name' or 'description', maybe even in 'label'. I can think of scenario when you have development and production template and you want to change the environment (even the name of services) based on the parameter value.

@smarterclayton does it make sense?