offline-deployment: Adapt ceph and prometheus for offline deployment

The adaptation is done by introducing 2 additional variable files for
both ceph and prometheus applications
- vars/offline-deployment.yaml
- vars/online-deployment.yaml

For ceph, cluster.yaml.j2, operator.yaml.j2, and toolbox.yaml.j2 templates
are updated and repositories and tags of the container images are parameterized
so the values are taken from the variable files depending on execution mode.

For prometheus, values file is templated and again, the repositories and
tags for container images are parameterized in order to set them depending
on execution mode.

Istio is not adapted since we need to migrate from helm based installation
to istioctl based approach since helm based installation will be deprecated.

https://istio.io/docs/setup/install/helm/

provisioner-type: bifrost
installer-type: kubespray
deploy-scenario: k8-calico-nofeature

Change-Id: Ic872dca3c09526ffc169e0c52163bd2bf89e7074
12 files changed