Infrastructure | Unify usage and generation of standard message metadata

[kzu]

The Command/Event buses use the IMetadataProvider to retrieve standard metadata from a message payload. This is the place where we would grab things like the assembly simple name, namespace, and type name of the payload, for filtering purposes.

But currently, the azure event store repository does not use this approach, meaning published event sourcing events will lack metadata that does exist for other messages.

We should consistently inject metadata into messages in all producers.

Requires updating the table storage for the event store so that this metadata dictionary is persisted too so that it's published to the bus too.