Add "yellow" pool status

Currently we have a green circle in the pool list if the pool is "healthy": true and red circle otherwise.

We need to show a yellow circle if pool is "healthy": true , but also has "warning": true . We need also to show status_detail somehow in that case to help the user understand why the pool is not completely healthy. Example of status_detail text:

One or more devices is currently being resilvered. The pool will continue to function, possibly in a degraded state.