docs: Fix all credential documentation urls, and add a CI job to regularly validate these urls (#5012)

* add or update documentation URLs for all credentials

* add UTM params to documentation urls even when they are absolute urls

* Setup a CI job to validate documentation urls after every release

* Fix FacebookGraphApi documentation URL

* also validate node documentation urls

Co-authored-by: Jan Oberhauser <jan.oberhauser@gmail.com>

packages/nodes-base/nodes/Cron/Cron.node.json

@@ -7,7 +7,7 @@
 	"resources": {
 		"primaryDocumentation": [
 			{
-				"url": "https://docs.n8n.io/integrations/builtin/core-nodes/n8n-nodes-base.cron/"
+				"url": "https://docs.n8n.io/integrations/builtin/core-nodes/n8n-nodes-base.scheduletrigger/"
 			}
 		],
 		"generic": [