remove configmap from kubernetes/gcp/system.yaml

[samos123]

This is required for having an installation flow that creates the configmap as part of the flow. For example, I would like to do this in the installation guide:

create and apply a configmap:

kubectl apply -f - << EOF
apiVersion: v1
kind: ConfigMap
metadata:
  name: system
  namespace: substratus
data:
  CLOUD: gcp
  ARTIFACT_BUCKET_URL: gs://$PROJECT_ID-substratus-artifacts
  REGISTRY_URL: us-central1-docker.pkg.dev/my-project/substratus # auto configured
  # CLUSTER_NAME: substratus auto configured
  # PRINCIPAL: substratus@my-project.iam.gserviceaccount.com auto configured
  # PROJECT_ID: my-project auto configured
  # CLUSTER_LOCATION: us-central1 auto configured
EOF

and then tell user to install the operator:

kubectl apply -f kubernetes/gcp/system.yaml

So the issue here is that kubectl apply -f kubernetes/gcp/system.yaml shouldn't also include that same configmap. This PR removes the configmap from kubernetes/gcp/system.yaml