Show consumer count column on Mgmt UI Channels page

Consumer count is already returned by the /channels API endpoint. Now
the consumer count column can be shown in the channels table but it is
hidden by default.

(cherry picked from commit b62e098)
(cherry picked from commit 31b9ecb)

Author: gomoripeti

deps/rabbitmq_management/priv/www/js/global.js

@@ -96,6 +96,7 @@ var ALL_COLUMNS =
                    ['mode',  'Mode',      true],
                    ['state', 'State',     true]],
       'Details': [['msgs-unconfirmed', 'Unconfirmed', true],
+                  ['consumer-count',   'Consumer count', false],
                   ['prefetch',         'Prefetch',    true],
                   ['msgs-unacked',     'Unacked',     true]],
       'Transactions': [['msgs-uncommitted', 'Msgs uncommitted', false],

deps/rabbitmq_management/priv/www/js/tmpl/channels-list.ejs

@@ -35,6 +35,9 @@
 <% if (show_column('channels', 'msgs-unconfirmed')) { %>
     <th><%= fmt_sort('Unconfirmed',     'messages_unconfirmed') %></th>
 <% } %>
+<% if (show_column('channels', 'consumer-count')) { %>
+    <th><%= fmt_sort('Consumer count', 'consumer_count') %></th>
+<% } %>
 <% if (show_column('channels', 'prefetch')) { %>
     <th>Prefetch <span class="help" id="channel-prefetch"></span></th>
 <% } %>
@@ -85,6 +88,9 @@
 <% if (show_column('channels', 'msgs-unconfirmed')) { %>
     <th>Unconfirmed</th>
 <% } %>
+<% if (show_column('channels', 'consumer-count')) { %>
+    <th>Consumer count</th>
+<% } %>
 <% if (show_column('channels', 'prefetch')) { %>
     <th>Prefetch <span class="help" id="channel-prefetch"></span></th>
 <% } %>
@@ -152,6 +158,9 @@
 <% if (show_column('channels', 'msgs-unconfirmed')) { %>
     <td class="c"><%= channel.messages_unconfirmed %></td>
 <% } %>
+<% if (show_column('channels', 'consumer-count')) { %>
+    <td class="c"><%= channel.consumer_count %></td>
+<% } %>
 <% if (show_column('channels', 'prefetch')) { %>
     <td class="c">
       <% if (channel.prefetch_count != 0) { %>