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 ;-)
I had private `regexpVal` variable defined in template pkg. Because of that I had to create public `ValidateUsingRegexpVal()` function in the template pkg as well. Because of this, I had to require template pkg from validation pkg. But the template pkg required the validation pkg, thus circular dependency.

I probably need to move the  `regexpVal` variable into the api pkg and make it public.