Refactors language translation link settings

- Strips whitespace around language code setting so any amount of
spacing can be introduced into the settings and the app won’t silently
not configure the language code URL properly.
- Adds ability to remove all language links and the app won’t break.
Ties into #483.
- Edits language links code comments to be consistent with other
settings in the settings file and adds a space after the colon in the
settings to be consistent with Ruby style guide key/value styling.