Migrate all KGO CRDs to this repository

[czeslavo]

Problem Statement

As part of KGO 1.4, we decided to keep KGO's CRDs' in this repository. New types were added here, but the old ones remained in the KGO repo.

This issue's goal is to move all the remaining KGO's CRDs to this repository. This will make the kubernetes-configuration repository a single source of truth for KGO's API and will allow us to generate its API reference from here.

Proposed Solution

• Add all CRDs from KGO to kubernetes-configuration repository
• Adapt KGO to use those and remove definitions in the KGO repo
• Move the API reference generator script to kubernetes-configuration

Acceptance Criteria

• https://github.com/Kong/gateway-operator/tree/main/api is moved to kubernetes-configuration repository
• https://github.com/Kong/gateway-operator/tree/main/api is removed from KGO and types from kubernetes-configuration are used
• KGO API markdown reference script is moved to the kubernetes-configuration repository