Add support for automatic logging at the beginning and end of subflows

[claytonflesher]

Just as v2 has automatic logging for beginning and end of flows, add support for this in subflows as well.
Use the same flow logs checkbox there is now, just for subflows.

[manikmagar]

Flow execution logging is based on the notifications provided by the runtime. There are no similar notifications for Subflow which ultimately just executes in the same context as the calling flow. We could check flow-ref processor notifications and see if logging the start and end of that processor will help. Although, when calling async actions, the logs may not represent sub-flows execution.

[manikmagar]

@adesjardin @claytonflesher We implemented flow-ref span capture for the OTEL module by using a flow-ref interceptor and detecting if the target is a sub-flow or flow. We could use the same strategy to enable sub-flow start and end logs.

[manikmagar]

This can also be done with notifications for a flow-ref processor with sub-flow as a target. Log the start and end of the flow-ref processor with the target name.