Added alert banners when connection is lost

apps/explorer_web/assets/css/app.scss

@@ -43,6 +43,7 @@ $fa-font-path: "~@fortawesome/fontawesome-free/webfonts";
 @import "node_modules/bootstrap/scss/forms";
 @import "node_modules/bootstrap/scss/tooltip";
 @import "node_modules/bootstrap/scss/badge";
+@import "node_modules/bootstrap/scss/alert";
 
 //Custom theme
 @import "theme/fonts";

apps/explorer_web/lib/explorer_web/templates/address_transaction/index.html.eex

@@ -72,14 +72,14 @@
 
       <div class="card-body">
         <div data-selector="channel-batching-message" style="display:none;">
-          <button data-selector="reload-button">
+          <div data-selector="reload-button" class="alert alert-info">
-            <span data-selector="channel-batching-count"></span> <%= gettext "more messages have come in" %>
+            <a href="#" class="alert-link" data-selector="channel-batching-count"><%= gettext "More messages have come in" %></a>
-          </button>
+          </div>
         </div>
         <div data-selector="channel-disconnected-message" style="display:none;">
-          <button data-selector="reload-button">
+          <div data-selector="reload-button" class="alert alert-danger">
-            <%= gettext "connection lost, click to load newer transactions" %>
+            <a href="#" class="alert-link"><%= gettext "Connection Lost, click to load newer transactions" %></a>
-          </button>
+          </div>
         </div>
         <div class="dropdown float-right u-push-sm">
           <button data-test="filter_dropdown" class="button button--secondary button--xsmall dropdown-toggle" type="button"