feat: automatic adoption of existing K8s resources

[mumoshu]

#6 would allow us to adopt existing K8s resources as if they were installed by helm. Let's go one step further by extending helm x apply to automatically run helm x adopt on first apply:

helm x apply \
  --adopt-resources myns/deployment/myapp,myns/service/myapp \
  --name myapp
  ./mychart

When the release myapp does not exist on your cluster, this runs helm x adopt --resources myns/deployment/myapp,myns/service/myapp and then helm x apply --name myapp ./mychart.

On second and further runs helm-x just runs helm x apply --name myapp ./mychart.

This way, users can run helm x apply whenever they need to install/upgrade a helm release, regardless of it needs to adopt first or not.