Add controller for EventGatewayDataPlane to manage keg deployments

[alacuku]

Problem Statement

Implement the controller reconciliation logic that translates EventGatewayDataPlane resources into running keg data plane deployments with proper Konnect connectivity.

Deploying keg manually requires coordinating multiple Kubernetes resources (Deployment, Service, ConfigMap, Secret) and complex bootstrapping (fetching cluster ID and region from Konnect, provisioning certificates, generating configuration YAML). The controller automates this entire workflow based on a single declarative resource