[clarity/consistency] rename /explorev2/ -> /explore/ (#2802)

* rename /explorev2/ -> /explore/

* add redirect for existing explorev2 urls

* fix long line

* remove extra line

* fix missed ref in spec

superset/assets/javascripts/SqlLab/components/VisualizeModal.jsx

@@ -8,7 +8,7 @@ import { Alert, Button, Col, Modal } from 'react-bootstrap';
 import Select from 'react-select';
 import { Table } from 'reactable';
 import shortid from 'shortid';
-import { getExploreUrl } from '../../explorev2/exploreUtils';
+import { getExploreUrl } from '../../explore/exploreUtils';
 import * as actions from '../actions';
 
 const CHART_TYPES = [
@@ -285,4 +285,3 @@ function mapDispatchToProps(dispatch) {
 
 export { VisualizeModal };
 export default connect(mapStateToProps, mapDispatchToProps)(VisualizeModal);
-

superset/assets/javascripts/modules/superset.js

@@ -2,8 +2,8 @@
 import $ from 'jquery';
 import Mustache from 'mustache';
 import vizMap from '../../visualizations/main';
-import { getExploreUrl } from '../explorev2/exploreUtils';
-import { applyDefaultFormData } from '../explorev2/stores/store';
+import { getExploreUrl } from '../explore/exploreUtils';
+import { applyDefaultFormData } from '../explore/stores/store';
 
 const utils = require('./utils');
 

superset/assets/javascripts/syncBackend.js

@@ -1,7 +1,7 @@
 /* eslint no-console: 0 */
 import fs from 'fs';
 import path from 'path';
-import { controls } from './explorev2/stores/controls';
+import { controls } from './explore/stores/controls';
 
 function exportFile(fileLocation, content) {
   fs.writeFile(fileLocation, content, function (err) {