Add Sentry Traces to covers

We currently have openlibrary.org giving us sentry traces to monitor performance across the sites. Let's add it to covers.openlibrary.org as well since it has seen some performance issues lately.

### Describe the problem that you'd like solved

### Proposal & Constraints

### Additional context
See #7130 . We shouldn't need as much work; we'll just need to add the `SentryProcessor` to `bind_to_webpy_app` (which is what covers, infogami use), and then experiment a bit. We might not be able to use the same `find_route` function, since coverstore doesn't use infogami but pure web.py

### Stakeholders