feat: emit "parsed" cloud events for OCS TSCH messages

[andrewdolce]

Summary of changes

Asana Ticket: Modify Trike to produce new parsed messages

This is a draft, but I would love to get feedback / a sanity check before I go further.

Changes:

• Adds the ocs directory, which contains modules for parsing the comma-delimited OCS format into Elixir structs representing the different message types. This was lifted directly from RTR, with a few modifications to remove things we likely wouldn't want Trike doing (like mapping lat/long to a list of location IDs.) The motivation in keeping it mostly unchanged from RTR is that I imagine potentially someday we might want a shared module with these struct definitions.

• Adds the cloud_events directory, with modules for formatting the OCS types into JSON to match the proposed schema here. I built this in a way to try to support future cases where we might need to emit multiple versions of a given event, for backward compatibility.

• Modifies cloud_events.ex to emit both the original raw messages and the new parsed messages.

I realize that splitting the OCS parsing and CloudEvent formatting into two layers might seem over-engineered, and there is maybe a lot of boilerplate, so definitely open to feedback on these points. Again, my reasons for doing it this way are to (1) potential for code reuse with RTR and (2) allowing for multiple versions of each cloud event.

Still TODO:

• Unit tests for the new message types
• Add TMOV messages (this just pulls in TSCH for now)
• (Likely) move parsing into its own supervised process and publish to separate kinesis stream

Reviewer Checklist

• Any new or changed functions have typespecs
• Tests were added for any new functionality (don't just rely on Lcov)
• Meets ticket's acceptance criteria