feat(parse): add Parse.StopEvents

[runkelcorey]

Part 3 disaggregating #973

Summary of changes

Asana Ticket: 📸↩︎ interpret flashback outputs (Parse.StopEvents

Adds Parse.StopEvents to structure JSON strings as Model.StopEvent structs.

How were these changes validated?

1. Wrote tests for Parse.StopEvents

What questions should reviewers consider?

1. Is this the appropriate amount and type of logging to provide?
2. Should I add any more documentation?
3. For my own Elixir journey: at what point should I stick attributes inside functions, to mitigate compilation times?