Add FluentBit pipeline for Keycloak account events.

[Sancus]

Process Keycloak authentication events (logins, token introspections, registrations) received from the Accounts Celery worker and forward them to PostHog. Events arrive at /telemetry/keycloak and are processed by a Lua filter and then sent to the PostHog batch API.

[Sancus]

My understanding is that the VPC Peering needs to be done in a two step process?

[Sancus]

Hmm. I'm not sure this is the correct approach. On further investigation, it doesn't seem like it's going to be possible for fluent-bit to enrich Stalwart-sourced events with keycloak uuids without adding additional connections to other resources.

If, instead, product analytics are routed through thunderbird-accounts and then directly to posthog, it's easy to enrich any submitted events with any data we want since acocunts has access to basically everything.

Given that, I'm not sure what value fluent-bit is providing to this pipeline.