Add a new module for "GKE Github Actions Connector"

[Jelledb]

I would basically love an Google Cloud (GKE) version of this Building Block: https://hub.meshcloud.io/definitions/aks-github-connector

App Teams in my organization always have to do some repetitive tasks to get an e2e GKE deployment running:

• Get access to container registry
• Get Registry Secrets into GitHub Actions Environment
• Get K8S Service Account + Put Credentials in GitHub Actions Environment