Adding missing Anti-Xsrf token validations in some Post actions

1. Also adding this validation on a AJAX only used action.
Ignore my previous comment. It has some inaccuracy. 

[ValidateAntiForgeryToken] needs both the antixsrf cookie as well as the form body parameter named __RequestVerificationToken. Since the call to this action is being made from javascript - we did not use @Html.AntiForgeryToken() helper to generate an antixsrf token in the form of a <input /> element. So the choice is to generate an antiforgery token and send it as a body parameter to validate it in the action as I have done.