Prominent warning box added to the DBConsole Overview

**Is your feature request related to a problem? Please describe.**
Some features on CockroachDB act like a ticking bomb. For example, certificates eventually expire, licenses expire, etc. It's possible as a user to get this information but it involves scraping the Prometheus metrics to get them (and also knowing what even to look for).

**Describe the solution you'd like**
The following events should have big red scary-looking panel right on the DBConsole Overview page:

- Certificate is close to expiring
- Certificate has expired
- License key has expired
- Other?

This panel would only appear when at least one problem exists. We can add more error messages to this in the future as we think of them.

relates to https://github.com/cockroachdb/cockroach/issues/99584

Jira issue: CRDB-25873