Refactor outcome comments to match logic docs

- Changed all the comments for each outcome in the yaml to match the logic docs.
- Changed all the comments for each outcome in the ruby file to match the logic docs.
- Outcomes are now all commented dependent upon whether the user is going abroad or is currently abroad.
- This should make it easier to follow the doc for any future changes.
Refactor comments for all questions in uk benefits abroad

- Changed all the comments for each question to match the logic docs.
- Should now be able to find the corresponding question whenever updates are required.
Merge pull request #1040 from alphagov/uk-benefits-refactor

Refactor UK Benefits Abroad to match logic documents