Add & configure ESlint; incl. plugins

Issue 2096

eslint.config.mjs

@@ -0,0 +1,30 @@
+import globals from "globals";
+import pluginJs from "@eslint/js";
+import prettierConfig from "eslint-config-prettier";
+import requirejs from "eslint-plugin-requirejs";
+
+export default [
+  {
+    name: "ignore-external-dependencies",
+    ignores: ["src/components/"]
+  },
+  {
+    name: "lint-views-models-and-collections",
+    files: ["src/**/*.js"],
+    plugins: {
+      requirejs
+    },
+    languageOptions: {
+      sourceType: "commonjs",
+      ecmaVersion: 2020,
+      globals: {
+        ...globals.browser,
+        ...globals.amd,
+        MetacatUI: "readonly",
+      }
+    },
+    rules: requirejs.configs.recommended.rules
+  },
+  pluginJs.configs.recommended,
+  ...[].concat(prettierConfig),
+];