Health/readiness probes configuration and improvements

[dotansimha]

At the moment, health and readiness are exposed in a static route paths, without the option to customize.

Customizations requires:

• Ability to run health/readiness endpoints in an "internal" service (another port and host). This is needed in order to allow runtime (K8s/docker) to access the health check, without exposing it publicly.
• Ability to customize paths for each check

probes:
  http:
     host: "0.0.0.0"
     port: 5000
  health:
     path: "/healthz"
  readiness:
     path: "/am-i-ready"