[FEAT shoot-grafter] - Migrate shoot-grafter workflows to kubebuilder with go-makefile-maker integration

[mikolajkucinski]

Priority

(Medium) I'm annoyed but I'll live

Description

• Create a separate folder for the kubebuilder-generated Makefile
• Include the kubebuilder Makefile in the go-makefile-maker Makefile using the verbatim feature
• Disable vendoring in go-makefile-maker configuration
• Retain existing GitHub workflows from go-makefile-maker
• Configure automatic container image builds on commits to the main branch
• Continue using make check target from go-makefile-maker
• Remove the OSPO reuse GitHub workflow and replace it with go-makefile-maker's add-license-headers functionality

Reference Issues

No response

[uwe-mayer]

merge draft PR.

• remove vendor directory
• include kubebuilder makefile into g-m-m