Highlight that DDL operations are asynchronous

The creation of scopes and collections are asynchronous. So there is a chance that if you create a collection right after creating a scope, it will fail.

If you create a collection and right after create an index on it, it can (and most likely will) fail, as the couchbase's services didn't have enough time to communicate with each other.

This issue has been reported on MB-46643

In the meantime, we need to highlight somewhere on our docs that these errors might occur and provide a temporary solution for it, otherwise, users that are creating scopes/collections/indexes dynamically will have a hard time with this issue.