Fieldsets to group form elements better

WIP.

Grouping radios, inputs and checkboxes a little more explicit. There is no visual change.

Needs more work also a bit more on the aria side.

Employment page not completed yet
Fieldsets to group form elements better

Employment page updates

- new fieldsets
- removed unused labels from locale
- made new locale entries
- fixed failing tests
Minor tweaks for labels
Merge pull request #375 from ministryofjustice/front-end/fieldsets-labels

Front end/fieldsets labels