use Kubernetes password secret if possible, fallback to env vars
use Kubernetes password secret if possible, fallback to env vars

Fixes #1

Signed-off-by: Mathias Merscher <51b7769398c961c3906a8358a3bad9abd27e7567@dg-i.net>

madddi/iib-bestpractice-runtimes,dennisseidel/iib-bestpractice-runtimes