Add localContentManger and dummy sessionManager (#3130)

* - keyboard binding to arrow keys
- toggle markdown editor by double click

* Added localContentManger and dummpy sessionManager

src/sql/services/notebook/sessionManager.ts

@@ -0,0 +1,31 @@
+'use strict';
+
+import { nb } from 'sqlops';
+import { Session } from 'electron';
+
+export class SessionManager implements nb.SessionManager {
+	private _sessionManager: nb.SessionManager;
+
+	constructor() {
+		
+	}
+	public get isReady(): boolean {
+		return this._sessionManager.isReady;
+	}
+
+	public get ready(): Thenable<void> {
+		return this._sessionManager.ready;
+	}
+	public get specs(): nb.IAllKernels {
+		return this._sessionManager.specs;
+	}
+
+	startNew(options: nb.ISessionOptions): Thenable<nb.ISession> {
+		return this._sessionManager.startNew(options);
+	}
+
+	shutdown(id: string): Thenable<void> {
+		return this.shutdown(id);
+	}
+
+}