Auth Strategies (#1257)

* auth strategies

* default to no auth

* rename base auth strategy

* rename base strategy cont.

* refactor auth strategy methods and LocalAuth

* activate old session options even if is falsy value

* move restartOnAuthFail to LegacyAuthStrategy option

* add link to guide item

* update example/shell

* types

example.js

@@ -1,17 +1,10 @@
-const { Client, Location, List, Buttons } = require('./index');
+const { Client, Location, List, Buttons, LocalAuth } = require('./index');
 
-const client = new Client({ 
-    clientId: 'example',
+const client = new Client({
+    authStrategy: new LocalAuth(),
     puppeteer: { headless: false }
 });
 
-// You also could connect to an existing instance of a browser
-// { 
-//    puppeteer: {
-//        browserWSEndpoint: `ws://localhost:3000`
-//    }
-// }
-
 client.initialize();
 
 client.on('qr', (qr) => {