Update eslint, and consistently format all JS code (#7170)

Author: DennisOSRM

.eslintignore

@@ -0,0 +1,28 @@
+const { Linter } = require("eslint");
+
+/** @type {Linter.Config} */
+const config = [
+    {
+        rules: {
+            indent: ["error", 2],
+            quotes: ["warn", "single"],
+            "linebreak-style": ["error", "unix"],
+            semi: ["error", "always"],
+            "no-console": ["warn"]
+        },
+        languageOptions: {
+            globals: {
+                es6: true,
+                node: true
+            }
+        },
+        ignores: [
+            "node_modules/",
+            "build/",
+            "dist/",
+            "coverage/"
+        ]
+    }
+];
+
+module.exports = config;