Feature Request: Flow "finally" or "error" path

[yippie]

Feature Type

I'm interested in functionality that solves a current problem or limitation in how CumulusCI works.

Does your feature request solve a current problem?

For complex flows or MetaDeploy plans, if something goes wrong, it could leave an org in a partial change or broken state. Sometimes there are things that can be done to correct, roll back, or notify of this happening.

Describe the solution you'd like

Request

Add an option to flows (that also works in MetaDeploy) to specify a task to always run, even if a previous tasks errors, or run only if an error happens. Bonus, but not required, if the error message, task, and step that failed can be provided somehow to the error task.

Use cases:

1. email admin that it failed and org is in a bad state until fixed
2. Delete/undo some metadata changes to "roll back" the partial change
3. Restore backed up metadata to a state before the upgrade

Describe alternatives you've considered

Writing entire flow as one giant custom task Manual error instructions on failure.

Additional context

No response