'Full Name' field in the signup form is allowing HTML as an input
which makes spoofing easily.To avoid it, validation is added
that will ensure 'Full Name' field does not allow HTML.
LEARNER-3385
Input forms that need validation will have AJAX requests
performed to get validation decisions live.
All but a few important and common form fields perform
generic validation; these will need a back-end handler
in the future in order to have them validated through AJAX requests.
Information is conveyed on focus and blur for both
errors and successes.
