* Adds workspace proxy section to health page
* Conditionally places workspace proxy warnings in errors or warnings based on calculated severity
* Adds some more stories we were missing for HealthPage
Adds a health check for workspace proxies:
- Healthy iff all proxies are healthy and the same version,
- Warning if some proxies are unhealthy,
- Error if all proxies are unhealthy, or do not all have the same version.
