feat(modal): improve accessibility - add role='dialog'

Author: pkozlowski-opensource

template/modal/window.html

@@ -1,3 +1,3 @@
-<div tabindex="-1" class="modal fade" ng-class="{in: animate}" ng-style="{'z-index': 1050 + index*10, display: 'block'}" ng-click="close($event)">
+<div tabindex="-1" role="dialog" class="modal fade" ng-class="{in: animate}" ng-style="{'z-index': 1050 + index*10, display: 'block'}" ng-click="close($event)">
     <div class="modal-dialog" ng-class="{'modal-sm': size == 'sm', 'modal-lg': size == 'lg'}"><div class="modal-content" ng-transclude></div></div>
 </div>