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.

clientonly/index.js

@@ -7,7 +7,8 @@
 	/**
 	 * Helper function to get server address/hostname from either the commandline or env
 	 */
-	function getServerAddress() {
+	function getServerAddress () {
+
 		/**
 		 * Get command line parameters
 		 * Assumes that a cmdline parameter is defined with `--key [value]`
@@ -15,7 +16,7 @@
 		 * @param {string} defaultValue value if no key is given at the command line
 		 * @returns {string} the value of the parameter
 		 */
-		function getCommandLineParameter(key, defaultValue = undefined) {
+		function getCommandLineParameter (key, defaultValue = undefined) {
 			const index = process.argv.indexOf(`--${key}`);
 			const value = index > -1 ? process.argv[index + 1] : undefined;
 			return value !== undefined ? String(value) : defaultValue;
@@ -35,7 +36,7 @@
 	 * @param {string} url location where the server is running.
 	 * @returns {Promise} the config
 	 */
-	function getServerConfig(url) {
+	function getServerConfig (url) {
 		// Return new pending promise
 		return new Promise((resolve, reject) => {
 			// Select http or https module, depending on requested url
@@ -64,7 +65,7 @@
 	 * @param {string} message error message to print
 	 * @param {number} code error code for the exit call
 	 */
-	function fail(message, code = 1) {
+	function fail (message, code = 1) {
 		if (message !== undefined && typeof message === "string") {
 			console.log(message);
 		} else {
@@ -121,4 +122,4 @@
 	} else {
 		fail();
 	}
-})();
+}());