Implement the reCAPTCHA element in the Samples project

Description

This is reCAPTCHA element for Episerver Forms

• It is open-sourced at Episerver Github.
• To configure this element, you need a site key and a secret key. Access these values when you register your site with reCAPTCHA (https://www.google.com/recaptcha).
• If you use reCAPTCHA without configuring it, a site visitor cannot pass the validation.

reCAPTCHA requires JavaScript to work.

• This element must run in JS mode because it rendered and validated using JavaScript.
• If you use reCAPTCHA in non-js mode, the validation for that element fails, and the form cannot be submitted.