allow user update slice name in dashboard view (#3467)

- if current user is allowed to edit dashboard, we will allow this user to edit slice name.
- show different tooltip given allowed/not-allowed to update slice name.
- user will click slice name and update.
- after user submit edit, if he doesn't have right to alter slice, server-side will return error message to client-side. Slice name will not be changed or saved.
- will show notification after save slice name.

superset/assets/javascripts/dashboard/components/Header.jsx

@@ -30,6 +30,7 @@ class Header extends React.PureComponent {
               title={dashboard.dashboard_title}
               canEdit={dashboard.dash_save_perm}
               onSaveTitle={this.handleSaveTitle}
+              noPermitTooltip={'You don\'t have the rights to alter this dashboard.'}
             />
             <span is class="favstar" class_name="Dashboard" obj_id={dashboard.id} />
           </h1>