Redo port of forms code from vets-website

[annekainicUSDS]

The original port I completed became out of sync because new changes continued to be merged into vets-website and it became unmanageable to keep the two versions of the codebase in sync while we waited to switch applications on Vets.gov to use the new repo. Redoing the port while we implement a code freeze for a few days on vets-website to keep the port clean.

[annekainicUSDS]

Things that remain to be changed on vets-website:

• Remove getInactivePages and use the version in us-forms-system in HCA
• Remove timeFromNow
• Remove PrivacyAgreement
• Remove schemaform-utils.jsx

Things that remain to be changed in us-forms-system:

• Move unit test for timeFromNow into helpers unit test file
• References to __BUILDTYPE__ --> right now this exists only in SubmitButtons.jsx
• Write a new, generic version of SubmitButtons, it's too specific to Vets.gov

[annekainicUSDS]

Complete