Remove built-in navigation template (facebook#21155)

Summary:
This is an updated (rebased) version of the very old facebook#16579.

I added a [template](https://github.com/facebook/react-native/tree/master/local-cli/templates/HelloNavigation) for react-navigation directly into the React Native repo a long time ago. The feature `react-native init --template foo` supports both:
- Remote templates (`react-native-template-foo` in npm as well as HTTP URLs)
- Local templates that ship with react-native itself

In retrospect, adding the local template wasn't a good idea. Templates should live outside of the React Native repo and be versioned independently. This way templates can be fixed independently of React Native releases, and people can use new templates without having to upgrade React Native.
Pull Request resolved: facebook#21155

Differential Revision: D9885719

Pulled By: hramos

fbshipit-source-id: d2982f374d3c451c09e348ce5fcdca9d0be5a474

Author: mkonicek

local-cli/generator/templates.js

@@ -14,45 +14,6 @@ const execSync = require('child_process').execSync;
 const fs = require('fs');
 const path = require('path');
 
-/**
- * Templates released as part of react-native in local-cli/templates.
- */
-const builtInTemplates = {
-  navigation: 'HelloNavigation',
-};
-
-function listTemplatesAndExit(newProjectName, options) {
-  if (options.template === true) {
-    // Just listing templates using 'react-native init --template'.
-    // Not creating a new app.
-    // Print available templates and exit.
-    const templateKeys = Object.keys(builtInTemplates);
-    if (templateKeys.length === 0) {
-      // Just a guard, should never happen as long builtInTemplates
-      // above is defined correctly :)
-      console.log(
-        'There are no templates available besides ' +
-          'the default "Hello World" one.',
-      );
-    } else {
-      console.log(
-        'The available templates are:\n' +
-          templateKeys.join('\n') +
-          '\nYou can use these to create an app based on a template, for example: ' +
-          'you could run: ' +
-          'react-native init ' +
-          newProjectName +
-          ' --template ' +
-          templateKeys[0],
-      );
-    }
-    // Exit 'react-native init'
-    return true;
-  }
-  // Continue 'react-native init'
-  return false;
-}
-
 /**
  * @param destPath Create the new project at this path.
  * @param newProjectName For example 'AwesomeApp'.
@@ -92,41 +53,7 @@ function createProjectFromTemplate(
   // This way we don't have to duplicate the native files in every template.
   // If we duplicated them we'd make RN larger and risk that people would
   // forget to maintain all the copies so they would go out of sync.
-  const builtInTemplateName = builtInTemplates[template];
-  if (builtInTemplateName) {
-    // template is e.g. 'navigation',
-    // use the built-in local-cli/templates/HelloNavigation folder
-    createFromBuiltInTemplate(
-      builtInTemplateName,
-      destPath,
-      newProjectName,
-      yarnVersion,
-    );
-  } else {
-    // template is e.g. 'ignite',
-    // use the template react-native-template-ignite from npm
-    createFromRemoteTemplate(template, destPath, newProjectName, yarnVersion);
-  }
-}
-
-// (We might want to get rid of built-in templates in the future -
-// publish them to npm and install from there.)
-function createFromBuiltInTemplate(
-  templateName,
-  destPath,
-  newProjectName,
-  yarnVersion,
-) {
-  const templatePath = path.resolve(
-    'node_modules',
-    'react-native',
-    'local-cli',
-    'templates',
-    templateName,
-  );
-  copyProjectTemplateAndReplace(templatePath, destPath, newProjectName);
-  installTemplateDependencies(templatePath, yarnVersion);
-  installTemplateDevDependencies(templatePath, yarnVersion);
+  createFromRemoteTemplate(template, destPath, newProjectName, yarnVersion);
 }
 
 /**
@@ -264,6 +191,5 @@ function installTemplateDevDependencies(templatePath, yarnVersion) {
 }
 
 module.exports = {
-  listTemplatesAndExit,
   createProjectFromTemplate,
 };

local-cli/init/init.js

@@ -10,7 +10,6 @@
 'use strict';
 
 const {
-  listTemplatesAndExit,
   createProjectFromTemplate,
 } = require('../generator/templates');
 const execSync = require('child_process').execSync;
@@ -44,14 +43,8 @@ function init(projectDir, argsOrName) {
   const newProjectName = args[0];
   const options = minimist(args);
 
-  if (listTemplatesAndExit(newProjectName, options)) {
-    // Just listing templates using 'react-native init --template'
-    // Not creating a new app.
-    return;
-  } else {
-    console.log('Setting up new React Native app in ' + projectDir);
-    generateProject(projectDir, newProjectName, options);
-  }
+  console.log('Setting up new React Native app in ' + projectDir);
+  generateProject(projectDir, newProjectName, options);
 }
 
 /**