Add a promotional message banner and events list

Add the banner back but update it for the Denver summit.

Co-Authored-By: Jeremy Stanley <fungi@yuggoth.org>
Change-Id: Ia80a290d53e117f960f7f57964d92252c605972c

www/assets/css/main.css

@@ -1881,13 +1881,20 @@ input[type="button"],
   height: 28em;
   text-align: center;
   position: relative; }
-  #banner header {
+  #banner p {
-    position: absolute;
+    display: inline-block;
-    bottom: 30%;
+    margin: 0;
-    left: 0;
     width: 100%;
-    color: #071d49;
+    vertical-align: middle;
+    background: #212121;
+    background: rgba(27, 27, 27, 0.75);
+    color: #37c0fb;
     padding: 1.5em 0; }
+    #banner p .button {
+      margin-left: 1em; }
+  #banner header {
+    color: #071d49;
+    margin: 6%; }
     #banner header h2 {
       display: inline-block;
       margin: 0;

www/community.html

@@ -60,6 +60,16 @@
                   <h2>Join the Community</h2>
                 </header>
 
+                <h3>Meet the Zuul Community at These Events</h3>
+                <p>Join the Zuul community where you can meet developers, get
+                   on-boarded as a contributor and learn from users running
+                   Zuul in production:</p>
+                <ul>
+                    <li><a href="https://www.openstack.org/summit/denver-2019/summit-schedule/global-search?t=zuul"
+                            >Open Infrastructure Summit</a>, April 29 - May 1, 2019,
+                             Denver, Colorado, USA</li>
+                </ul>
+
                 <h3>Join the Mailing List</h3>
   	        <a href="http://lists.zuul-ci.org/cgi-bin/mailman/listinfo" class="image right"><img src="images/lists.png" alt="" /></a>
                 <p>Zuul has <a href="http://lists.zuul-ci.org/cgi-bin/mailman/listinfo">mailing lists</a> for announcements and discussions.</p>

www/index.html

@@ -54,6 +54,12 @@
 
       <!-- Banner -->
         <section id="banner">
+          <p>
+            <strong>Meet the Zuul Community at the Open Infrastructure Summit, April 29 -
+                May 1 in Denver, Colorado!</strong>
+            <a href="https://www.openstack.org/summit/denver-2019/summit-schedule/global-search?t=zuul"
+              class="button">Learn More</a>
+          </p>
           <header>
             <h2>Stop Merging Broken Code</h2>
           </header>