fix: remove old boilerplate code for simple screen

Author: ethanneff

src/__tests__/index.tsx

@@ -0,0 +1,8 @@
+import "react-native";
+import React from "react";
+import { Main } from "..";
+import renderer from "react-test-renderer";
+
+it("renders correctly", () => {
+  renderer.create(<Main />);
+});

src/components/Instructions/__tests__/__snapshots__/index.tsx.snap

@@ -1,14 +1,22 @@
-// app entry
-import { AppRegistry, Platform } from "react-native";
-import { App } from "./screens";
-import { Config } from "./utils";
+import React, { memo } from "react";
+import { AppRegistry, View, Text, Platform, StyleSheet } from "react-native";
 
-// register the app
-AppRegistry.registerComponent(Config.app.name, () => App);
+const appName = "example";
+const styles = StyleSheet.create({
+  container: { flex: 1, justifyContent: "center", alignItems: "center" }
+});
 
-// register the web
-if (Platform.OS === Config.os.web) {
-  AppRegistry.runApplication(Config.app.name, {
-    rootTag: document.getElementById(Config.web.root)
+export const Main = memo(function Main() {
+  return (
+    <View style={styles.container}>
+      <Text>react native with web and typecript</Text>
+    </View>
+  );
+});
+
+AppRegistry.registerComponent(appName, () => Main);
+if (Platform.OS === "web") {
+  AppRegistry.runApplication(appName, {
+    rootTag: document.getElementById("root")
   });
 }