Internationalization

[mark-dce]

STORY
As an application developer, I would like all added UI text to be easily replaceable via yaml file, so that I don't have to edit code directly to change UI language or wording.

DETAILS
Follow the existing pattern for internationalization in blacklight. Ask Justin or Jesse Keck if you need additional examples on how to do this

ACCEPTANCE

• Added or changed text for links to view or manage folders in the header is configurable by setting appropriate entries in / config / locales / blacklight.en.yml - etc.
• Added descriptive text on folder show and edit pages is configurable in locales
• Added button text, link text, etc. is configurable in locales

NOTE: only English localizations need to be provided
i.e. we should try to avoid string literals for the UI in the codebase.

[mark-dce]

I think we still need to add things like
"Folders" at https://github.com/curationexperts/blacklight_folders/blob/master/app/views/blacklight/folders/catalog/_folder_controls.html.erb#L7
"This item is contained in:" at https://github.com/curationexperts/blacklight_folders/blob/master/app/views/blacklight/folders/catalog/_folder_controls.html.erb#L28
"item" at https://github.com/curationexperts/blacklight_folders/blob/master/app/views/blacklight/folders/folders/_folder.html.erb#L5
Confirmation message at https://github.com/curationexperts/blacklight_folders/blob/master/app/views/blacklight/folders/folders/_folder.html.erb#L12
etc.

Re-opening and blocking this story until we have the UI complete.