[#162105][WIP] Tech Task: Handle mime type errors

[giladshanan]

Release Notes

This type of error pops up from time to time, the result of a security scan. This refactors error handling to a more modern pattern, while at the same time handling mime type errors properly so they don't create noise in Rollbar.

See:

• https://guides.rubyonrails.org/configuring.html#config-exceptions-app
• https://web-crunch.com/posts/custom-error-page-ruby-on-rails
• https://mattbrictson.com/blog/handling-rails-exceptions

To Do

• Remove unused boiler plate from generator
• Add and/or update specs
• Local testing of mime type handling

[LeticiaErrandonea]

Couldn't fix the specs, but it looks like a config issue (works for local but consistently fails for test env).

I tried recommendations here and didn't work. Issue is that the ErrorsController doesn't get hit when the exception is raised.