Add ESLint and the ESLint import plugin

Add the ESLint import plugin to automatically sort Vue.js imports in
the Dashboard code.

After installing ESLint I ran `npx eslint --fix .` to auto-format files
where possible.

dashboard/eslint.config.mjs

@@ -0,0 +1,42 @@
+import globals from "globals";
+import pluginJs from "@eslint/js";
+import tseslint from "typescript-eslint";
+import pluginVue from "eslint-plugin-vue";
+import pluginImport from "eslint-plugin-import";
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+  { files: ["**/*.{js,mjs,cjs,ts,vue}"] },
+  {
+    settings: {
+      "import/resolver": {
+        typescript: { project: "tsconfig*.json" },
+      },
+    },
+  },
+  { languageOptions: { globals: globals.browser } },
+  pluginJs.configs.recommended,
+  pluginImport.flatConfigs.recommended,
+  ...tseslint.configs.recommended,
+  ...pluginVue.configs["flat/essential"],
+  {
+    files: ["**/*.{ts,vue}"],
+    languageOptions: { parserOptions: { parser: tseslint.parser } },
+    rules: {
+      "import/no-unresolved": [
+        "error",
+        {
+          ignore: ["~icons"], // ignore unplugin-icon auto import paths.
+        },
+      ],
+      "vue/multi-word-component-names": "off", // doesn't work with auto-router paths.
+      "import/order": [
+        "error",
+        {
+          alphabetize: { order: "asc" },
+          "newlines-between": "always",
+        },
+      ],
+    },
+  },
+];