Admin instance-level page: List project overrides table

Description

As part of #213857 (closed), we introduce a feature called Project using custom settings which gives admins visibility into projects which projects are using different settings other than what they have set.

Proposal

1. Have a way for administrators to see which projects are using the default configuration and which projects have a different config.

In later iterations, we will

1. Add a "Use default settings" button for each project that is using custom settings
2. Add a button that sets all projects using custom settings to use default settings

For mockups, see the Designs section below.

Checklist

• Can we remove the code added with !61678 (merged)?

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