Draft: Project settings: Re-write delete project section

What does this MR do?

The content in the delete project and delayed project sections needs a re-write so that it's clear how to:

• Delayed project deletion is duplicated across Groups and visibility and access settings, with a different story in each. Need to get those consistent.
• Difference between an immediate project deletion and marking a project for deletion. Does marking a project for deletion only work if delayed deletion is enabled?
• Make more clear the implications for deleting a project.

Related issues

#363733 (closed)

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