V2 - Add undo() and redo() on useParcelBuffer / useParcelForm

[dxinteractive]

We're storing all the users actions as actions in a stack anyway, so this shouldn't be difficult.

• sort out what to do post-submit to retain ability to still undo
  • send changes but dont store them in state?
  • send changes as normal but keep old change requests in buffer to go back through?
• keyboard bindings for Ctrl+Z as an optional thing would be great

[dxinteractive]

• Simplify buffer by storing an array of actions (or objects that contain actions, which could also contain snapshots), not a change request
• Do not clear buffer on submit, do it on receipt of new data
  • New data should perform a setData and just push it onto the stack, rather than replacing
• Store an index of the active action (0 or less) to support redos
• Add a history param that sets the minimum number of actions to remember