Release v19.27.0

Added

• Opt-in MongoDB database isolation with storage.databaseNamePrefix, covering Chronicle databases, read models, jobs, and Orleans cluster state while leaving existing names unchanged by default. Connection strings are used unchanged. See MongoDB database-name prefix configuration. (part of #4126)
• Storage.MongoDB.Specs can run against an external MongoDB through CHRONICLE_MONGODB_CONNECTION_DETAILS, using unique database names and removing only the databases they create. See Running against an external MongoDB. (part of #4126)

Fixed

• Event-store, namespace, and read-model connections now authenticate using the connection string's authentication database, or admin when none is specified, instead of the target database. Credentials without authSource now use the original connection string's authentication scope, including when no database-name prefix is configured. (part of #4126)