Replace Passenger 404, 500, ect pages

[kilahimm]

Provide GW branded or more meaningful error pages for passenger to serve.

[kerchner]

The 404 page looks pretty good and the links to the contact page and help page seem to work - try https://scholarspace.library.gwu.edu/asdfasdf

I'd have to think about how to provoke an error 500 response.

[kilahimm]

It's probably more the 500 error pages, basically situations in which the rails app fails all together. Granted we wouldn't expect these in production, but they can happen.

[kerchner]

Ah, right. And so then those would be more a passenger configuration, as you noted.

[kerchner]

Closing as a wontfix. This will be done in GWSS 2.0 with gwu-libraries/scholarspace-sufia7#37