Refactor Cluster Application classes to pass through a has of config files

What does this MR do?

This is refactoring in the lead up to passing mutual TLS certs for helm applications for #48098 (closed). As such we expect all applications to need config files so we can remove the logic about which applications need and do not need this (ie #config_map?).

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated
• [-] API support added
• Tests added for this feature/bug
• Conforms to the code review guidelines
  • [-] Has been reviewed by a UX Designer
  • [-] Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • [-] Has been reviewed by a Database specialist
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

#48098 (closed)