Endpoint to get a specific resource's events as SSE

**Motivation**
It is currently possible to watch all resources events within a project using SSE. However it is not possible to watch events of a specific resource.

**Acceptance criteria**
1. It is possible to get the events related to a single resource as SSE

Start by locating the existing SSE endpoint that watches all resource events within a project, then trace how resource identifiers and event streams are handled. Done means a request can subscribe to events for one specific resource via SSE, with coverage for the stated acceptance criterion.

Written by the indexing model from the issue text.