feat(ux): replace spinners (#1383)

app/directives/buttonSpinner.js

@@ -0,0 +1,14 @@
+angular
+.module('portainer')
+.directive('buttonSpinner', function buttonSpinner() {
+  var directive = {
+    restrict: 'A',
+    scope: {
+      spinning: '=buttonSpinner'
+    },
+    transclude: true,
+    template: '<ng-transclude></ng-transclude><span ng-show="spinning"><i class="fa fa-circle-o-notch fa-spin" style="margin-left: 2px;"></i>&nbsp;</span>'
+  };
+
+  return directive;
+});