Update to eslint 9

- Update eslint
- Update webpack and eslint-webpack-plugin
- Update the eslint config file to the new format

Signed-off-by: David Thompson <davthomp@redhat.com>

eslint.config.mjs

@@ -0,0 +1,44 @@
+// @ts-check
+
+import eslint from '@eslint/js';
+import tseslint from 'typescript-eslint';
+import globals from "globals";
+
+export default tseslint.config(
+  eslint.configs.recommended,
+  tseslint.configs.recommended,
+  {
+    ignores: [
+      "node_modules/**",
+      "dist/**",
+      "server/**",
+      "out/**",
+    ],
+  },
+  {
+    files: [ "src/**/*" ],
+    rules: {
+      "@typescript-eslint/no-unused-vars": [
+        "warn",
+        {
+          "argsIgnorePattern": "^_",
+          "caughtErrorsIgnorePattern": "^_"
+        }
+      ],
+      "@typescript-eslint/no-explicit-any": "warn",
+    }
+  }, {
+    files: [
+      "gulpfile.js",
+      "webpack.config.js"
+    ],
+    languageOptions: {
+      sourceType: "commonjs",
+      globals: globals.node
+    },
+    rules: {
+      "@typescript-eslint/no-var-requires": "off",
+      "@typescript-eslint/no-require-imports": "off"
+    }
+  }
+);

gulpfile.js

@@ -53,10 +53,6 @@ function isMac() {
   return /^darwin/.test(process.platform);
 }
 
-function isLinux() {
-  return /^linux/.test(process.platform);
-}
-
 function mvnw() {
   return isWin() ? "mvnw.cmd" : server_dir + "/mvnw";
 }