Explicit state machines for multistep user stories

[wpbonelli]

E.g., binding an agent or workflow, or configuring and submitting a workflow. Will also be helpful for image annotations. Currently we just construct ad hoc logic in the view. It would probably be better to use an explicit FSM so we can emit transition events in a standardized way across the whole app.

options:

• https://github.com/statelyai/xstate
• https://github.com/etgryphon/stativus
• https://github.com/jakesgordon/javascript-state-machine