Add jsonnet configuration files

[fpetkovski]

Jsonnet configuration for the prometheus adapter is currently managed in kube-prometheus. Do we want to migrate the bulk of it to this repository and simply import it in kube-prometheus instead?

[dgrisonnet]

Yes, that's the direction we want to go with in kube-prometheus. This effort is currently tracked in 2 different tasks, one to first update the manifests and deployment instructions and then an effort to migrate to jsonnet and generate the manifests:

• Update deployment manifests and instructions #426
• Generate deployment manifests from jsonnet  #427

[fpetkovski]

Closing as duplicate