dashfolder: fix after backendSrv change

also removes unused create folder modal

public/app/features/dashboard/create_folder_ctrl.ts

@@ -20,7 +20,7 @@ export class CreateFolderCtrl {
     return this.backendSrv.createDashboardFolder(title).then(result => {
       appEvents.emit('alert-success', ['Folder Created', 'OK']);
 
-      var folderUrl = `/dashboards/folder/${result.id}/db/${result.slug}`;
+      var folderUrl = `/dashboards/folder/${result.dashboard.id}/${result.meta.slug}`;
       this.$location.url(folderUrl);
     });
   }

public/app/features/dashboard/folder_modal/folder.html

-<div class="modal-body">
-  <div class="modal-header">
-    <h2 class="modal-header-title">
-			<i class="gicon gicon-folder-new"></i>
-      <span class="p-l-1">New Dashboard Folder</span>
-    </h2>
-
-    <a class="modal-header-close" ng-click="ctrl.dismiss();">
-      <i class="fa fa-remove"></i>
-    </a>
-  </div>
-
-  <form name="ctrl.saveForm" ng-submit="ctrl.create()" class="modal-content folder-modal" novalidate>
-    <div class="p-t-2">
-      <div class="gf-form">
-        <input type="text" ng-model="ctrl.title" required give-focus="true" class="gf-form-input" placeholder="Enter folder name" />
-      </div>
-    </div>
-    <div class="gf-form-button-row text-center">
-      <button type="submit" class="btn btn-success" ng-disabled="ctrl.saveForm.$invalid">Create</button>
-      <a class="btn-text" ng-click="ctrl.dismiss();">Cancel</a>
-    </div>
-  </form>
-</div>

public/app/features/dashboard/folder_modal/folder.ts

-import coreModule from 'app/core/core_module';
-import appEvents from 'app/core/app_events';
-
-export class FolderCtrl {
-  title: string;
-  dismiss: any;
-
-  /** @ngInject */
-  constructor(private backendSrv, private $location) {
-  }
-
-  create() {
-    if (!this.title || this.title.trim().length === 0) {
-      return;
-    }
-
-    const title = this.title.trim();
-
-    return this.backendSrv.createDashboardFolder(title).then(result => {
-      appEvents.emit('alert-success', ['Folder Created', 'OK']);
-      this.dismiss();
-
-      var folderUrl = '/dashboard/db/' + result.slug;
-      this.$location.url(folderUrl);
-    });
-  }
-}
-
-export function folderModal() {
-  return {
-    restrict: 'E',
-    templateUrl: 'public/app/features/dashboard/folder_modal/folder.html',
-    controller: FolderCtrl,
-    bindToController: true,
-    controllerAs: 'ctrl',
-    scope: {
-      dismiss: "&"
-    }
-  };
-}
-
-coreModule.directive('folderModal', folderModal);