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 ;-)
By doing this the package becomes a singleton.  We've made the blanket statement that singletons are bad, and that we're doing dependency injection.  So instead of having a factory, a client is going to do something like:

```
generators := []Generator{NewPasswordGenerator(), NewExpressionGenerator()}
processor := NewTemplateProcessor(generators)
config := processor.Process(templateConfig)
```