[Feature Request] Support user metadata

[cretz]

Describe the solution you'd like

See https://github.com/temporalio/features/issues/486. Specifically, after https://github.com/temporalio/sdk-core/issues/830:

• Accept optional "static summary " and "static details" on all ways to start a workflow (start, signal with start, schedule, and child workflow) and populate user metadata with them
• Accept optional "summary" when creating timers and populate user metadata with it
• Accept optional "summary" when creating activities and populate user metadata with it
• Handle __temporal_workflow_metadata query (see features issue and https://github.com/temporalio/sdk-go/pull/1597)
• Mark experimental