Add subscribe form to homepage

I want to get rid of the mailchimp-hosted page. For one, I can't even have a favicon.

I'll need a mailchimp form "component".

The form is hidden within.

Also need to reference and update the docs here:
- https://stackoverflow.com/questions/21526408/mailchimp-subscribe-using-jquery-ajax

References:
- https://mailchimp.com/help/host-your-own-signup-forms/