Revert "Add a promotional message banner and events list"

This reverts commit ba46e4f36646609060f0e1d514c80a3b4323d3cd.

There are currently no upcoming events to promote. This can be
un-reverted once we have something new we want listed, or perhaps
someone can figure out a better way to toggle the event banner
without needing deeper CSS changes to handle relative positioning of
the tagline text.

Change-Id: I3d1dc7dcc5ba8a2869a9a8890bf79275f332d559

www/assets/css/main.css

@@ -1881,20 +1881,13 @@ input[type="button"],
   height: 28em;
   text-align: center;
   position: relative; }
-  #banner p {
-    display: inline-block;
-    margin: 0;
-    width: 100%;
-    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 {
+    position: absolute;
+    bottom: 30%;
+    left: 0;
+    width: 100%;
     color: #071d49;
-    margin: 6%; }
+    padding: 1.5em 0; }
     #banner header h2 {
       display: inline-block;
       margin: 0;

www/community.html

@@ -60,16 +60,6 @@
                   <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/berlin-2018/summit-schedule/global-search?t=zuul"
-                            >OpenStack Summit</a>, November 13-15, 2018,
-                             Berlin, Germany</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

@@ -54,12 +54,6 @@
 
       <!-- Banner -->
         <section id="banner">
-          <p>
-            <strong>Meet the Zuul Community at the OpenStack Summit, November
-                13-15 in Berlin, Germany!</strong>
-            <a href="https://www.openstack.org/summit/berlin-2018/summit-schedule/global-search?t=zuul"
-              class="button">Learn More</a>
-          </p>
           <header>
             <h2>Stop Merging Broken Code</h2>
           </header>