I18N - find places where we have not used I18N and add copy to en.yml

[kasugaijin]

We started off well adding text displayed in the UI (view copy, alert messages, and active record error messages) in the I18n en.yml file, but then we got a bit forgetful.

This task is to look through the application and find cases where we should move text from a view to en.yml, a controller (e.g., alert messages), and also add copy in en.yml for active record validation error messages.

I am not specifying a set amount of work for this task as I don't know how many places this occurs. If you prefer, you can scope the work and report back, or just start making the changes and make a PR resource by resource.