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

src/authStrategies/BaseAuthStrategy.js

@@ -0,0 +1,24 @@
+'use strict';
+
+/**
+ * Base class which all authentication strategies extend
+ */
+class BaseAuthStrategy {
+    constructor() {}
+    setup(client) {
+        this.client = client;
+    }
+    async beforeBrowserInitialized() {}
+    async afterBrowserInitialized() {}
+    async onAuthenticationNeeded() {
+        return {
+            failed: false,
+            restart: false,
+            failureEventPayload: undefined
+        };
+    }
+    async getAuthEventPayload() {}
+    async logout() {}
+}
+
+module.exports = BaseAuthStrategy;