Enhance docs to explain differences between fetch from image vs. fetch from imgpkgBundle

[asaikali]

The docs on App CR High Level Overview shows all the places where configurations can be fetched from. Enhance the docs to explain what is the differences similarities between fetching from fetch from an image vs. fetch from imgpkgBundle

If the overview section is the wrong place to add this info, then maybe consider adding a page on fetching strategies with a discussion of the pros/cons of each approach to fetching.

[100mik]

It would be great to call out how Carvel tooling enables relocatable bundles while leveraging imgpkg with the Packaging APIs.

Especially calling out bits like how dependent images are relocated. And even how bundle references are recursed into. I am going to leave this for triage as this issue might not belong to this repository.
This is definitely something we want to take note of in our documentation more explicitly.

[github-actions]

This issue is being marked as stale due to a long period of inactivity and will be closed in 5 days if there is no response.

[renuy]

Moving to carvel repo for doc enhancements