Disable Grafana login

Might be optional and configurable via Helm.

See https://stackoverflow.com/questions/33111835/how-to-set-up-grafana-so-that-no-password-is-necessary-to-view-dashboards

mentioned in commit b5803592

assigned to @she

changed milestone to %0.5.0

Part of !83 (merged)

closed

mentioned in commit 94aaf3ce

mentioned in commit 72842097