Document the unbind-system-db command and add details about the system db in cluster (#2631)#2642

NataliaIvakina merged 1 commit intoneo4j:mainneo4j/docs-operations:mainfrom

NataliaIvakina:main-unbind-system-dbNataliaIvakina/docs-operations:main-unbind-system-dbCopy head branch name to clipboard