Add new safe health check that doesn't disclose any system info
Add new safe health check that doesn't disclose any system info

Added a new health check url that hides any detailed issues and
merely returns OK or DOWN for a healthcheck request, with
associated http codes of 200 and 500 respectively.

ONSdigital/eq-survey-runner,ONSdigital/eq-survey-runner,ONSdigital/eq-survey-runner,ONSdigital/eq-survey-runner