feat(footer): replace ghost newsletter sign up with mailchimp

* Turn autocompletion off, including lastpass and 1password
* Remove error/success styles

Author: sarmstead

partials/footer.hbs

@@ -10,12 +10,17 @@
             {{navigation type='secondary'}}
         </section>
         <section class='footer__bottom'>
-            <form class='footer__form' data-members-form='subscribe'>
+            <form
+                action='https://rubycentral.us13.list-manage.com/subscribe/post?u=e7e9b891a6914ff2f5acdfd15&amp;id=0a6a1336c5&amp;v_id=5118&amp;f_id=008ef4e7f0'
+                autocomplete='off'
+                class='footer__form'
+                method='post'
+            >
                 <div class='footer__form__row'>
                     <input
-                        data-members-email
-                        name='email'
-                        id='get-involved-email'
+                        data-lpignore='true'
+                        data-1p-ignore
+                        name='EMAIL'
                         placeholder='Enter your email...'
                         required='true'
                         type='email'
@@ -24,8 +29,6 @@
                         <button class='kg-btn' type='submit'>Sign Up</button>
                     </div>
                 </div>
-                <span data-members-error></span>
-                <span data-members-success></span>
             </form>
             <div class='footer__bottom__socials'>
                 <div class='footer__bottom__socials__links'>

src/css/layout/footer.css

@@ -64,25 +64,6 @@
         align-items: center;
         display: flex;
         flex-direction: column;
-
-        span[data-members-error],
-        span[data-members-success] {
-            display: none;
-            font-size: 0.875rem;
-            font-weight: 700;
-            line-height: 1rem;
-            padding: 16px 0;
-        }
-    }
-
-    .error span[data-members-error] {
-        color: var(--color-darkred);
-        display: block;
-    }
-
-    .success span[data-members-success] {
-        color: green;
-        display: block;
     }
 
     .footer__form__row {