Add API for listing all workflows *steps* #40
Description
At the moment workflowManager.status() only returns running (steps) for type: 'inProgress'.
Something like this is what I am after to be able to easily inspect the workflow step args and results.
// The return type for `workflowManager.status()`
export type WorkflowStatus = {
steps: OpaqueIds<Step>[] // <= suggesting to add
running: OpaqueIds<Step>[] // <= probably not needed if `steps` was added?
type: 'inProgress'
} | {
type: 'completed'
steps: OpaqueIds<Step>[] // <= add?
} | {
type: 'canceled'
steps: OpaqueIds<Step>[] // <= add?
} | {
error: string
type: 'failed'
steps: OpaqueIds<Step>[] // <= add?
}