Static Pages for 4xx and 5xx errors and proper error codes

[pgwillia]

Is your feature request related to a problem? Please describe.
Our error pages don't respond with the appropriate http response codes.

Describe the solution you'd like

discovery/config/routes.rb

Line 2 in 8ad3cdb

# TODO: These error routes should be deleted. Let rails handle this themselves with proper status codes

#1353

See neosdiscovery ualbertalib/NEOSDiscovery#229 and jupiter ualbertalib/jupiter#525