Improve backup creation UI

- Do not prompt the user if he really wants to create a backup
- Show error message if a backup can't be created at the moment

webadmin/src/views/settings.html

@@ -79,19 +79,18 @@
     </div>
 </div>
 
-<!-- Modal backup -->
-<div class="modal fade" id="createBackupModal" tabindex="-1" role="dialog">
+<!-- Modal backup failed -->
+<div class="modal fade" id="createBackupFailedModal" tabindex="-1" role="dialog">
     <div class="modal-dialog">
         <div class="modal-content">
             <div class="modal-header">
-                <h4 class="modal-title">Create a new Backup</h4>
+                <h4 class="modal-title">Unable to create backup</h4>
             </div>
             <div class="modal-body">
-                Do you really want to create a new backup?
+                {{ createBackup.errorMessage }}
             </div>
             <div class="modal-footer">
-                <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
-                <button type="button" class="btn btn-success" ng-click="createBackup.doCreateBackup()" ng-disabled="createBackup.busy"><i class="fa fa-spinner fa-pulse" ng-show="developerModeChange.busy"></i> Confirm</button>
+                <button type="button" class="btn btn-success" data-dismiss="modal">Ok</button>
             </div>
         </div>
     </div>
@@ -374,7 +373,7 @@
         <div class="col-xs-6 text-right">
             <button class="btn btn-outline btn-primary pull-right" ng-click="configureBackup.show()" ng-disabled="createBackup.busy">Configure</button>
 
-            <button class="btn btn-outline btn-primary" ng-click="createBackup.showCreateBackup()" ng-disabled="createBackup.busy" style="margin-right: 10px">Backup now</button>
+            <button class="btn btn-outline btn-primary" ng-click="createBackup.doCreateBackup()" ng-disabled="createBackup.busy" style="margin-right: 10px">Backup now</button>
         </div>
     </div>
 </div>