fix(kafka): add quotas

Author: RoRoJ

pages/clusters-for-kafka/faq.mdx

@@ -29,6 +29,7 @@ Private Beta is aimed at providing an early version of a future product, to allo
 - Storage is fixed at 100 GB per node.
 - Connectivity to the cluster is facilitated exclusively through Private Networks.
 - Only one set of credentials (username and password) can be created per cluster.
+- Each Scaleway Organization in the Private Beta may have a maximum of 5 clusters at one time (TODO CHECK)
 
 We aim to improve and develop the product based on feedback received during the beta stage.