DX & Workflows: Error handling and error'ed receipt handling

[zeeshanlakhani]

Summary

We need to work through failure handling around workflow completion, error notifications, and handling ok/err receipted instructions.

Components

• Default (as part of workflows) for the runner to abort the workflow early when resolving a promise fails (outside of the workflow).
• Make this an option/setting within the workflow for the workflow executor to control.
• If not ☝🏽, otherwise, we need to return and notify of errored receipts. However, we have to check the associated receipt's result (ok/err) if it's replayed from db/gossip/network. Also, Q if we want to store errors (or change the pruning level for them).