ISTWCMS-3706 Create mailman subscription form block

source/_patterns/04-components/mailman-subscription/_mailman-subscription.scss

+.uw-mailman {
+  padding: 1rem 0;
+  width: 100%;
+
+  &__label {
+    display: block;
+    font-family: "BureauGrotCond Book",impact,"avenir next condensed heavy","Droid Sans",sans-serif;
+    font-size: 1.26562rem;
+    font-weight: 400;
+    margin-bottom: .35rem;
+  }
+  &__servername {
+    text-align: center;
+  }
+}

source/_patterns/04-components/mailman-subscription/mailman-subscription.twig

+<div class="uw-mailman">
+  <form action="//{{ mailman.server }}/mailman/subscribe/{{ mailman.servername }}">
+    <div class="uw-mailman__label"><label for="{{ mailman.uniqueid }}">Email address:</label></div>
+    <div class="uw-mailman__email">
+      <input type="email" name="email" id="{{ mailman.uniqueid }}">
+      <input type="submit" value="Subscribe">
+    </div>
+  </form>
+</div>
\ No newline at end of file

source/_patterns/04-components/mailman-subscription/mailman-subscription.yml

+mailman:
+  server: 'lists.uwaterloo.ca (a.k.a. mailman.uwaterloo.ca)'
+  servername: 'uwweb'
+  uniqueid: '1111111'
\ No newline at end of file