Port Python get_event endpoint over to plugin server

[Twixes]

This is a (WIP) port of the get_event view function from Python to TypeScript, more precisely only its ee branch. The original runs our capture endpoint in the Django app but isn't compatible with plugin processing, this should allow for compatibility.

[mariusandra]

With regard to naming things, there are two parts of the stack that can both be called "ingestion":

• /e/ --> some queue (and then before plugins) .... aka "capture"
• some queue after plugins --> database ... aka "process_event"

The JS server should be able to do both ends, yet I think the process_event step is more important for now, since the first step is handled by Django. Even in EE we write the events to a Kafka topic in capture, which the plugin server could just read from. There's however no way to get events after plugin processing back into Django for the final process_event_ee step...

(That said the capture step as started in this PR is also very important to get done. If for nothing else, we can at least do better benchmarks when that's in place)

[Twixes]

This is super stale now.