Mount configmap in k8s as file as volume

[yrobla]

Right now, when we have the flag TOOLHIVE_USE_CONFIGMAP, what we are doing is having a --from-configmap in the thv runner, and we read the configmap, and translate this to runconfig. Instead what we can do if we have this flag, is just mount the configmap as a volume in the pod, and just check the runconfig from that file