Deploy only network cost DS into shoot cluster

[phyrog]

At the moment, all KubeCost components are deployed into the shoot cluster (including its own Prometheus).

This can be improved by leveraging the Prometheus and Plutono deployed in the seed cluster. Since the cost-analyzer needs query access to Prometheus, it makes sense to deploy the cost-analyzer into the seed cluster too. I believe the only component that needs to run in the shoot cluster is the network cost daemonset, as this will analyze the traffic going in and out of pods on the shoot nodes.

A few things that need investigating:

• are all the necessary metrics collected from node-exporter and cadvisor?
• do all metrics have the necessary labels?
• how can the kubecost manifests be split across seed/shoot while still make them easily updatable?