add linting config, and lint files before commit

.eslintrc.json

@@ -1,3 +1,73 @@
 {
-    "extends": "next/core-web-vitals"
+    "extends": [
+        "eslint:recommended",
+        "plugin:@next/next/recommended",
+        "airbnb",
+        "next/core-web-vitals",
+        "prettier",
+        "plugin:jsx-a11y/recommended"
+    ],
+    "plugins": ["react", "prettier"],
+    "parserOptions": {
+        "ecmaFeatures": {
+            "jsx": true
+        },
+        "ecmaVersion": 2020,
+        "sourceType": "module"
+    },
+    "rules": {
+        "no-underscore-dangle": "off",
+        "import/prefer-default-export": "off",
+        "react/jsx-no-bind": "off",
+        "react/no-unescaped-entities": "off",
+        "prettier/prettier": "error",
+        "react/react-in-jsx-scope": "off",
+        "react/jsx-props-no-spreading": "off",
+        "react/forbid-prop-types": "off",
+        "object-shorthand": "off",
+        "no-use-before-define": "off",
+        "react/require-default-props": [
+            "error",
+            {
+                "ignoreFunctionalComponents": true
+            }
+        ],
+        "singleQuote": "off"
+    },
+    "settings": {
+        "import/resolver": {
+            "alias": {
+                "extensions": [".js", ".jsx"],
+                "map": [["@/app", "./src/app"]]
+            }
+        },
+        "jsx-a11y": {
+            "polymorphicPropName": "as",
+            "components": {
+                "BodyLong": "p",
+                "BodyShort": "p",
+                "Button": "button",
+                "CheckboxGroup": "fieldset",
+                "Checkbox": "input",
+                "Chips": "ul",
+                "Heading": "h",
+                "Icon": "svg",
+                "IconButton": "button",
+                "Image": "img",
+                "Input": "input",
+                "Link": "a",
+                "List": "ul",
+                "ListItem": "li",
+                "NextImage": "img",
+                "NextLink": "a",
+                "Pagination": "nav",
+                "RadioGroup": "fieldset",
+                "Radio": "input",
+                "Select": "select",
+                "TextField": "input",
+                "Textarea": "textarea",
+                "Tooltip": "button"
+            }
+        }
+    }
 }

.stylelintrc.json

@@ -0,0 +1,3 @@
+{
+    "extends": ["stylelint-config-recommended", "@navikt/aksel-stylelint/recommended"]
+}