Add a Metro configuration with inline require/import

Summary:
We have been working on turning on inline-requires/imports and RAM bundles for React Native for a long time, however we have not made real progress on making it the default, even though it is easy. In this diff I am adding a Metro configuration to a new React Native template with the defaults set to `false` (off). This means that everyone creating a new project now or upgrading from an existing one will receive this template file. In a future release of React Native we will turn this setting on to default. From then on, new projects will be using inline-requires while existing ones that are upgrading can make an explicit choice when they are diffing their template and the latest version of it.

This approach was outlined in https://github.com/react-native-community/discussions-and-proposals/blob/master/core-meetings/2018-09-metro-meeting.md#actions-that-will-be-taken

Note: There is a weird lint-ignore thing in there like in the other template files. I'm working on getting rid of that separately.

Reviewed By: TheSavior

Differential Revision: D14030370

fbshipit-source-id: cf4c5551c795f2ea0fd1b731b352489f04b8c22e

template/metro.config.js

@@ -0,0 +1,18 @@
+/**
+ * Metro configuration for React Native
+ * https://github.com/facebook/react-native
+ *
+ * @format
+ * @lint-ignore-every XPLATJSCOPYRIGHT1
+ */
+
+module.exports = {
+  transformer: {
+    getTransformOptions: async () => ({
+      transform: {
+        experimentalImportSupport: false,
+        inlineRequires: false,
+      },
+    }),
+  },
+};