feat(neutron-api): template neutron-api k8s probes

This change allow users to customize neutron API Kubernetes probes in order to be able set another values based on environment.

In addition it adds new templating function `container_probes` to be able to set any container k8s probes if necessary.

Furthermore switch k8s probes from probing root bath of WSGI server of neutron-api to probe `/healthcheck` to be able to identify those requests in the logs and sorting them out during debugging or logging.

Signed-off-by: Mohamad Mouselli mohamad.mouselli@digits.schwarz