Edits to immigration drill down

[mollieru]

resolve:

• [ ] potential checklist approach
• [ ] could add military Q here
• [ ] add the specific Afghani/Iraqi category
• [ ] add: "Did you arrive prior to August 22, 1996?"
• [ ] change this to "check which applies to (if any)" -- a few will require follow ups
• [ ] add: LPR: "have you been for more than 5 years, if you're 18 and older?"
• [ ] add note about alerting USCIS of your presence

Full convo here, for reference: https://github.com/usds/enrollment/issues/207