Configurable parameters for liveness/readiness probes

Parameters for liveness and readiness probes should not be hardcoded in the statefulset template, but configurable via values.yaml

Current values used are:

livenessProbe:
    ...
    failureThreshold: 10
    initialDelaySeconds: 1000
    periodSeconds: 50

readinessProbe:
    ...
    initialDelaySeconds: 5
    periodSeconds: 5

Thresholds for the liveness probe need to be increased to avoid frequent restarts due to temporary network failures/delays.