add feature test for sign in audit
Audit authentication failures and successes

Improve auditing of authentication success and add auditing for failures.
Add audit messages for SMS success and failure

Also, clean up audit helper methods.
Merge branch 'devel' into feature/audit_auth_failure

Conflicts:
	db/schema.rb
move audit specs to requests/lib/controller

Move these out of features, because the specific logic can be tested in isolation.
clean up commented code
get provider from params instead of passing it as a string
clean up mobile recovery spec changes
Merge pull request #391 from 18F/feature/audit_auth_failure

Feature/audit auth failure