React better to network errors

[Danno Ferrin]

Right now when a network error occurs Numisight explorer silently consumes the error and doesn't tell the end user what happened. This could be because of bad network data (like when json is only half filled), because a HTTPS cert expired, or because we are getting rate limited.

We should add some sort of a way to tell the end user "errors are happening" and provide some information that could be useful to them, or at least to the support team.