Enable Site and Page Specific Design System Metadata Overrides and Additions

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Update Summary: Enable Site and Page Specific Design System Metadata Overrides and Additions
Check-in Date: MM/DD/YYYY (US format) [When we should see progress/get an update]
Due Date: MM/DD/YYYY (US format) [When the issue should be fully completed]
Blocked by: [#XXXXXX] (New issues on new lines)
Additional Collaborators: @username1, @username2
AI Tracker found here: https://www.drupalstarforge.ai/
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Problem/Motivation

Make sure the design system can be overridden or added to by a specific theme. Needs to be done in a structured manner so that with overrides, its still possible to update the underlying design system metadata without conflicts. We will need 3 levels. Core metadata, Custom Code Overrides, Site Config Overrides. We need AI to know to priorities higher level (config overrides) which the user has used. There will need to be permissions so that people who can use the overrides aren't the same people who can edit them.

Proposed resolution

Remaining tasks