Error Handling

[justincy]

The components don't do any error handling beyond console.error() logging. We need to come up with error states for the components as well as global error hooks or events.

[justincy]

In fs-webcomponents/sample-app#26 we added toast notifications to the sample app by listening to all fs-request response events that bubbled up. But the error messages are not particularly helpful. The best we can do is say there was an error and show the HTTP response status code and status text.

Ideally each component would listen for errors and attempt to provide a more helpful error message while also having its own error state.