Replace prettier by stylistic to lint JavaScript (#3303)

In the latest versions of ESLint, more and more formatting rules were
removed or declared deprecated. These rules have been integrated into
the new Stylistic package (https://eslint.style/guide/why) and expanded.

Stylistic acts as a better formatter  for JavaScript as Prettier.

With this PR there are many changes that make the code more uniform, but
it may be difficult to review due to the large amount. Even if I have no
worries about the changes, perhaps this would be something for the
release after next.

Let me know what you think.

js/loader.js

@@ -7,6 +7,7 @@
  * MIT Licensed.
  */
 const Loader = (function () {
+
 	/* Create helper variables */
 
 	const loadedModuleFiles = [];
@@ -196,10 +197,11 @@ const Loader = (function () {
 
 	/* Public Methods */
 	return {
+
 		/**
 		 * Load all modules as defined in the config.
 		 */
-		loadModules: async function () {
+		async loadModules () {
 			let moduleData = getModuleData();
 
 			/**
@@ -230,7 +232,7 @@ const Loader = (function () {
 		 * @param {Module} module The module that calls the loadFile function.
 		 * @returns {Promise} resolved when the file is loaded
 		 */
-		loadFileForModule: async function (fileName, module) {
+		async loadFileForModule (fileName, module) {
 			if (loadedFiles.indexOf(fileName.toLowerCase()) !== -1) {
 				Log.log(`File already loaded: ${fileName}`);
 				return;
@@ -256,4 +258,4 @@ const Loader = (function () {
 			return loadFile(module.file(fileName));
 		}
 	};
-})();
+}());