cluster_admin, bucket_admin can read analytics data

According to the description of the roles (cluster_admin and bucket_admin), they shouldn't be able to read any data. However, they currently can read analytics data as the analytics permissions aren't explicitly excluded from the roles. The current Analytics documentation (https://docs.couchbase.com/server/6.5/analytics/rest-analytics.html) mentions that cluster_admin can access several APIs and perform Analytics operation. However, when this fix is implemented, cluster_admin won't be able to perform any analytics operation which might cause a backward compatibility issue.