Examples in Java Documentation frequently use Administrator user against best practices

We do not generally recommend using the Administrator user in the Java SDK, even for development. And it can cause issues if used in specific circumstances as with [this example](https://docs.couchbase.com/java-sdk/2.7/sdk-user-management-example.html) in our documentation. If the following 2 pages could be changed in order to reflect that they should be using RBAC users with appropriate privileges rather than the Administrator user and a more general policy going forward, of using non-Admin users for examples this would be an improvement to prevent sending conflicting messages to customers.

Managing Clusters
SDK User Management