[explore] refactor slice action button group (#1074)

* pull explore actions button group into component

* use button component

* make sure we render all action buttons

* test that embed code is correct

* don't need before each

* generalize modal trigger for use with plain links or icons

caravel/assets/javascripts/SqlLab/components/TabbedSqlEditors.jsx

@@ -10,6 +10,7 @@ let queryCount = 1;
 
 class QueryEditors extends React.Component {
   renameTab(qe) {
+    /* eslint no-alert: 0 */
     const newTitle = prompt('Enter a new title for the tab');
     if (newTitle) {
       this.props.actions.queryEditorSetTitle(qe, newTitle);