[Oct 1] Remove Composer 1 metadata

Issue created by @drumm

drumm → committed 33e7b5f7 on 7.x-1.x

Issue #3460888: Remove Composer 1 root metadata

🇺🇸United States drumm NY, US

The initial deployment will remove Composer 1 support today. (Last week was a bit too busy for this.)

This issue will remain open to remove the supporting code and data in the next few days, assuming things go well.

drumm → committed 65dbe812 on 7.x-1.x

Issue #3460888: Update the composer 1 message

drumm → committed 67850c97 on 7.x-1.x

Issue #3460888: Remove last use of project_composer_providers table

drumm → committed 8a2bc31e on 7.x-1.x
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Issue #3460888: Remove unused variable
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drumm → committed 4fa853d9 on 7.x-1.x
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Issue #3460888: Remove unused function
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drumm → committed f6f4e884 on 7.x-1.x
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Issue #3460888: Remove unused tables
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drumm → committed aa18483b on 7.x-1.x

Issue #3460888: Remove unused file deletion

🇺🇸United States drumm NY, US

The Composer 1 metadata and supporting code are now removed.

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