Add liveness and readiness probes

[nvernooy]

AC:

• Add a custom status view to the backend deployment that returns 200 ok HTTP response
• Use the status view in the liveness and readiness probes for the backend deployment

Tech notes: Here is an example about how to do this in django Status probes will fail if the host does not match django allowed hosts. To get around this add a host header to liveness and readiness probes that shown in the example below

readinessProbe:
  httpGet:
    path: /health/
    port: 8000
    httpHeaders:
    - name: Host
      value: <your-allowed-hostname>