install dependencies

Summary:
In the previous implementation plugins were downloaded from npm, but dependencies weren't. This diff uses the `live-plugin-manager` which does mostly what we want. It install a package from NPM with all its dependencies.
live-plugin-manager puts the plugin and its dependencies in the same folder. We expect the plugins to be in `node_modules`. For this reason, we are installing the plugin into `$pluginName/node_modules` and move the plugin after the installation out of the `node_modules` folder.

* Fixed plugin loading path for thirdparty plugins.
* Disabled hot reloading for plugins in the flipper folder to prevent reloads when moving around files and installing dependencies here.
* an empty `.watchmanconfig` is created, because metro requires it
* tsx files are added to the list of supported extensions for metro

Reviewed By: passy

Differential Revision: D17570413

fbshipit-source-id: ecbedc60841b36188fec9c83da41ef1f27e5e155

types/live-plugin-manager.d.tsx

@@ -0,0 +1,73 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+export declare class PluginManager {
+  constructor(options?: Partial<LivePluginManager.PluginManagerOptions>);
+  install(
+    name: string,
+    version?: string,
+  ): Promise<LivePluginManager.IPluginInfo>;
+  readonly options: LivePluginManager.PluginManagerOptions;
+}
+
+declare namespace LivePluginManager {
+  interface IPluginInfo {
+    readonly mainFile: string;
+    readonly location: string;
+    readonly name: string;
+    readonly version: string;
+    readonly dependencies: {[name: string]: string};
+  }
+
+  interface PluginSandbox {
+    env?: NodeJS.ProcessEnv;
+    global?: NodeJS.Global;
+  }
+
+  export interface NpmRegistryAuthToken {
+    token: string;
+  }
+
+  export interface NpmRegistryAuthBasic {
+    username: string;
+    password: string;
+  }
+
+  interface NpmRegistryConfig {
+    auth?: NpmRegistryAuthToken | NpmRegistryAuthBasic;
+    userAgent?: string;
+  }
+
+  export interface GithubAuthUserToken {
+    type: 'token';
+    token: string;
+  }
+
+  export interface GithubAuthBasic {
+    type: 'basic';
+    username: string;
+    password: string;
+  }
+
+  export type GithubAuth = GithubAuthUserToken | GithubAuthBasic;
+
+  interface PluginManagerOptions {
+    cwd: string;
+    pluginsPath: string;
+    sandbox: PluginSandbox;
+    npmRegistryUrl: string;
+    npmRegistryConfig: NpmRegistryConfig;
+    npmInstallMode: 'useCache' | 'noCache';
+    requireCoreModules: boolean;
+    hostRequire?: NodeRequire;
+    ignoredDependencies: Array<string | RegExp>;
+    staticDependencies: {[key: string]: any};
+    githubAuthentication?: GithubAuth;
+    lockWait: number;
+    lockStale: number;
+  }
+}