Include Task Event ID in ETW and App Insights traces

[cgillum]

Is your feature request related to a problem? Please describe.
When looking at orchestration traces, it's not possible to distinguish one activity function call from another if they have the same name. This creates various challenges when doing end-to-end tracing.

Describe the solution you'd like
In the Durable Task Framework, each activity and sub-orchestration has an auto-incremented "event ID" that can be used to differentiate these tasks. These IDs should be included in the logs. Note that we already include this information in our internal DurableTask-AzureStorage ETW events, but those are not visible in the high-level Durable Functions traces.

Describe alternatives you've considered
We could expose the DurableTask-AzureStorage ETW traces (which have this information), but those are very low level and high-volume, making them harder for ordinary users to understand.