Port most notebook model code over to be behind a service (#3068)

- Defines a new NotebookService in Azure Data Studio which will be used to interact with notebooks. Since notebooks can require per-file instantiation the provider is just used to create & track managers for a given URI.
- Inject this into notebook.component.ts and pass required parameters that'll be used to properly initialize a manger into the method. Actual initialization not done yet.
- Port over & recompile notebook model code
- Define most required APIs in sqlops.proposed.d.ts. In the future, these will be used by extensions to contribute their own providers.

src/sql/services/notebook/notebookService.ts

@@ -0,0 +1,59 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import * as sqlops from 'sqlops';
+import { createDecorator } from 'vs/platform/instantiation/common/instantiation';
+import URI from 'vs/base/common/uri';
+import { IBootstrapParams } from 'sql/services/bootstrap/bootstrapService';
+
+export const SERVICE_ID = 'notebookService';
+export const INotebookService = createDecorator<INotebookService>(SERVICE_ID);
+
+export const DEFAULT_NOTEBOOK_PROVIDER = 'builtin';
+
+export interface INotebookService {
+	_serviceBrand: any;
+
+	/**
+	 * Register a metadata provider
+	 */
+	registerProvider(providerId: string, provider: INotebookProvider): void;
+
+	/**
+	 * Register a metadata provider
+	 */
+	unregisterProvider(providerId: string): void;
+
+	/**
+	 * Initializes and returns a Notebook manager that can handle all important calls to open, display, and
+	 * run cells in a notebook.
+	 * @param providerId ID for the provider to be used to instantiate a backend notebook service
+	 * @param uri URI for a notebook that is to be opened. Based on this an existing manager may be used, or
+	 * a new one may need to be created
+	 */
+	getOrCreateNotebookManager(providerId: string, uri: URI): Thenable<INotebookManager>;
+
+	shutdown(): void;
+}
+
+export interface INotebookProvider {
+	readonly providerId: string;
+	getNotebookManager(notebookUri: URI): Thenable<INotebookManager>;
+	handleNotebookClosed(notebookUri: URI): void;
+}
+
+export interface INotebookManager {
+	providerId: string;
+	readonly contentManager: sqlops.nb.ContentManager;
+	readonly sessionManager: sqlops.nb.SessionManager;
+	readonly serverManager: sqlops.nb.ServerManager;
+}
+
+export interface INotebookParams extends IBootstrapParams {
+	notebookUri: URI;
+	providerId: string;
+}