feat: bring back EXT:yoast_seo

Editors need its focus keyword and readability analysis in the page form.
Version 12.1 supports TYPO3 13.4 and keeps the existing tx_yoastseo_* data
of the TYPO3 10 database.

The deploy's extension:setup adds its new pages columns and tables. After
the deploy, run the upgrade wizard yoastDashboardWidgetMigrate (it moves the
yoast "pages without meta description" dashboard widget to the core one).

In the frontend, yoast adds WebSite and BreadcrumbList JSON-LD to every page.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

composer.json

@@ -49,7 +49,8 @@
 		"typo3/cms-sys-note": "^13.4",
 		"typo3/cms-tstemplate": "^13.4",
 		"typo3/cms-viewpage": "^13.4",
-		"typo3/cms-webhooks": "^13.4"
+		"typo3/cms-webhooks": "^13.4",
+		"yoast-seo-for-typo3/yoast_seo": "^12.1"
 	},
 	"repositories": [
 		{