chore: let Webpack to manage DateUtils.js

This makes possible to use Jest for JavaScript unit tests.

The public URL of DateUtils.js has been changed
from /public/js/$VERSION/DateUtils.min.js
to   /public/js/$VERSION/utils/DateUtils.min.js
and technically old cached code might search by the old location but as this file wasn't available
to anonymous users, the chances are extremely low.

Part of #1484

Author: php-coder

src/main/javascript/DateUtils.js src/main/frontend/src/utils/DateUtils.js

@@ -16,3 +16,5 @@ var DateUtils = {
 	}
 
 }
+
+window.DateUtils = DateUtils;

src/test/javascript/DateUtilsSpec.js src/main/frontend/src/utils/DateUtils.test.js

@@ -1,3 +1,5 @@
+import './DateUtils.js'
+
 describe('DateUtils.formatDateToDdMmYyyy()', function() {
 
 	it('should return a string in a format dd.mm.yyyy', function() {

src/main/frontend/webpack.config.js

@@ -1,23 +1,25 @@
 const path = require('path');
 const webpack = require('webpack');
 
-const SRC_DIR = './src/components/';
-
 // @todo #1455 Remove export of components to window
 module.exports = {
     mode: 'production',
     entry: {
-        AddCatalogNumbersForm: SRC_DIR + 'AddCatalogNumbersForm.js',
-        AddCatalogPriceForm:   SRC_DIR + 'AddCatalogPriceForm.js',
-        AddCommentForm:        SRC_DIR + 'AddCommentForm.js',
-        AddReleaseYearForm:    SRC_DIR + 'AddReleaseYearForm.js',
-        HideImageForm:         SRC_DIR + 'HideImageForm.js',
-        SeriesSaleImportForm:  SRC_DIR + 'SeriesSaleImportForm.js',
-        SeriesSalesList:       SRC_DIR + 'SeriesSalesList.js',
-        SimilarSeriesForm:     SRC_DIR + 'SimilarSeriesForm.js'
+        'utils/DateUtils':                  './src/utils/DateUtils.js',
+
+        'components/AddCatalogNumbersForm': './src/components/AddCatalogNumbersForm.js',
+        'components/AddCatalogPriceForm':   './src/components/AddCatalogPriceForm.js',
+        'components/AddCommentForm':        './src/components/AddCommentForm.js',
+        'components/AddReleaseYearForm':    './src/components/AddReleaseYearForm.js',
+        'components/HideImageForm':         './src/components/HideImageForm.js',
+        'components/SeriesSaleImportForm':  './src/components/SeriesSaleImportForm.js',
+        'components/SeriesSalesList':       './src/components/SeriesSalesList.js',
+        'components/SimilarSeriesForm':     './src/components/SimilarSeriesForm.js'
     },
     output: {
-        path: path.resolve(__dirname, '../../../target/classes/js/components'),
+        // As we can't have a dynamic output path, we've included a subdirectory in entry names. See:
+        // https://stackoverflow.com/questions/35903246/how-to-create-multiple-output-paths-in-webpack-config
+        path: path.resolve(__dirname, '../../../target/classes/js'),
         filename: '[name].min.js'
     },
     module: {

src/main/java/ru/mystamps/web/feature/site/ResourceUrl.java

@@ -37,7 +37,7 @@ public final class ResourceUrl {
 	// CheckStyle: ignore LineLength for next 17 lines
 	private static final String CATALOG_UTILS_JS      = "/public/js/" + RESOURCES_VERSION + "/CatalogUtils.min.js";
 	private static final String COLLECTION_INFO_JS     = "/public/js/" + RESOURCES_VERSION + "/collection/info.min.js";
-	private static final String DATE_UTILS_JS          = "/public/js/" + RESOURCES_VERSION + "/DateUtils.min.js";
+	private static final String DATE_UTILS_JS          = "/public/js/" + RESOURCES_VERSION + "/utils/DateUtils.min.js";
 	private static final String MAIN_CSS               = "/static/"    + RESOURCES_VERSION + "/styles/main.min.css";
 	private static final String PARTICIPANT_ADD_JS     = "/public/js/" + RESOURCES_VERSION + "/participant/add.min.js";
 	private static final String SERIES_ADD_JS          = "/public/js/" + RESOURCES_VERSION + "/series/add.min.js";

src/main/webapp/WEB-INF/views/series/info.html

@@ -878,7 +878,7 @@ <h5 th:text="#{t_add_info_who_selling_series}">Add info about selling/buying thi
 		<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js" th:src="${BOOTSTRAP_JS}"></script>
 
 		<script sec:authorize="hasAnyAuthority('VIEW_SERIES_SALES', 'IMPORT_SERIES_SALES')"
-			src="../../../../javascript/DateUtils.js"
+			src="../../../../../../target/classes/js/utils/DateUtils.min.js"
 			th:src="${DATE_UTILS_JS}"></script>
 
 		<script sec:authorize="hasAuthority('VIEW_SERIES_SALES')"