feat: replace install job by apl-operator

[CasLubbers]

📌 Summary

• Added an installer class to the apl-operator which executes the installation
• After installation is done the git credentials secrets are created and passed down to operator
• Removed retry mechanism in install function as its now done in installer
• Removed bootstrapping in operator and is now done in installer
• Installing is not done when its finished
• Welcome message is now posted in configmap.
• There is not waiting/checking anymore if APL is functional that must now be done by the user itself.

🔍 Reviewer Notes

🧹 Checklist

• Code is readable, maintainable, and robust.
• Unit tests added/updated

[ElderMatt]

I have the following error during an upgrade from 4.12.0 to this branch.