add logs viewer for email server

src/views/email.html

@@ -532,6 +532,18 @@
         </div>
 
         <div class="card card-large" style="margin-bottom: 15px;" ng-show="selectedDomain.provider !== 'caas'">
+          <div class="row">
+            <div class="col-md-12">
+              <h4>Email Server Logs</h4>
+              <p>
+                Logs are for all email domains on this Cloudron.
+              </p>
+              <button type="button" class="btn btn-primary" ng-click="showLogs()">Show Logs</button>
+            </div>
+          </div>
+
+          <br/>
+
           <div class="row">
             <div class="col-md-12">
               <h4>SMTP Status</h4>

src/views/email.js

@@ -30,6 +30,10 @@ angular.module('Application').controller('EmailController', ['$scope', '$locatio
         { name: 'PTR', value: 'ptr' }
     ];
 
+    $scope.showLogs = function () {
+        window.open('/logs.html?id=mail', 'Logs', 'width=1024,height=800').focus();
+    };
+
     $scope.showView = function (view) {
         // wait for dialog to be fully closed to avoid modal behavior breakage when moving to a different view already
         $('.modal').on('hidden.bs.modal', function () {