Allow configurable prefix for MDC keys

The SDK writes around 21 MDC keys like WorkflowId, Namespace, TaskQueue, Attempt.
These names aren't configurable.

Ask is for an SDK option to add a prefix to them. Blank by default for backwards
compatibility.

The only workaround today is renaming keys in the logging config, which doesn't fully work:

• Matches are on key name only. An app that sets its own Namespace key gets that value
  relabelled to temporal.Namespace, even though it didn't come from Temporal.
• Every key a new SDK release adds — NexusService and NexusOperation, for example — has
  to be added to the rename list by hand, and there's nothing to tell you it's missing.

If possible make this a WorkerFactory setting so it applies to all workers created from it.

One thing to watch: 19 of the keys are constants in LoggerTag, but ReplayWorkflowExecutor
writes "Signals" and "Updates" as string literals. A prefix applied only to LoggerTag
would skip those.