feat(app): add nativewind support (#19)

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#### What this PR does / why we need it:

Add `nativewind` support as opposed to `tailwind-rn`, you can use
`className` directly and babel will takecare of it.

```tsx
import { View } from 'react-native';

export default function App(): JSX.Element {
  return (
    <View className="flex-1 items-center justify-center bg-white">
    </View>
  );
}
```

app/app.d.ts

@@ -0,0 +1,4 @@
+/**
+ * This file is used to declare global types for your application.
+ */
+/// <reference types="nativewind/types" />

app/babel.config.js

@@ -2,5 +2,6 @@ module.exports = function (api) {
   api.cache(true);
   return {
     presets: ['babel-preset-expo'],
+    plugins: ['nativewind/babel'],
   };
 };

app/package.json

@@ -33,15 +33,18 @@
   "dependencies": {
     "@babel/core": "^7.20.0",
     "@types/react": "~18.0.27",
+    "@types/react-native": "^0.72.2",
     "expo": "~48.0.18",
     "expo-status-bar": "~1.4.4",
+    "nativewind": "^2.0.11",
     "react": "18.2.0",
     "react-native": "0.71.3",
-    "typescript": "4.9.5"
+    "typescript": "^4.9.4"
   },
   "devDependencies": {
     "@levain-keychain/eslint-config": "0.0.0",
     "eas-cli": "^3.13.3",
-    "expo-cli": "^6.3.8"
+    "expo-cli": "^6.3.8",
+    "tailwindcss": "^3.3.2"
   }
 }

app/src/App.tsx

@@ -1,20 +1,11 @@
 import { StatusBar } from 'expo-status-bar';
-import { StyleSheet, Text, View } from 'react-native';
+import { Text, View } from 'react-native';
 
 export default function App(): JSX.Element {
   return (
-    <View style={styles.container}>
-      <Text>KeyChain — Open up App.js to start working on your app!</Text>
+    <View className="flex-1 items-center justify-center bg-white">
+      <Text className="font-medium">KeyChain — Open up App.js to start working on your app!</Text>
       <StatusBar style="auto" />
     </View>
   );
 }
-
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: '#fff',
-    alignItems: 'center',
-    justifyContent: 'center',
-  },
-});

app/tailwind.config.js

@@ -0,0 +1,8 @@
+/** @type {import('tailwindcss').Config} */
+module.exports = {
+  content: ['./src/**/*.{js,jsx,ts,tsx}'],
+  theme: {
+    extend: {},
+  },
+  plugins: [],
+};