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/parts/notebook/notebookInput.ts

@@ -1,21 +1,39 @@
+/*---------------------------------------------------------------------------------------------
+ *  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 { TPromise } from 'vs/base/common/winjs.base';
 import { IEditorModel } from 'vs/platform/editor/common/editor';
 import { EditorInput, EditorModel, ConfirmResult } from 'vs/workbench/common/editor';
-
 import { Emitter, Event } from 'vs/base/common/event';
+import URI from 'vs/base/common/uri';
 
 export type ModeViewSaveHandler = (handle: number) => Thenable<boolean>;
 
 export class NotebookInputModel extends EditorModel {
 	private dirty: boolean;
 	private readonly _onDidChangeDirty: Emitter<void> = this._register(new Emitter<void>());
-	get onDidChangeDirty(): Event<void> { return this._onDidChangeDirty.event; }
-
-	constructor(public readonly modelViewId, private readonly handle: number, private saveHandler?: ModeViewSaveHandler) {
+	private _providerId: string;
+	constructor(public readonly notebookUri: URI, private readonly handle: number, private saveHandler?: ModeViewSaveHandler) {
 		super();
 		this.dirty = false;
 	}
 
+	public get providerId(): string {
+		return this._providerId;
+	}
+
+	public set providerId(value: string) {
+		this._providerId = value;
+	}
+
+	get onDidChangeDirty(): Event<void> {
+		return this._onDidChangeDirty.event;
+	}
+
 	get isDirty(): boolean {
 		return this.dirty;
 	}
@@ -55,8 +73,12 @@ export class NotebookInput extends EditorInput {
 		return this._title;
 	}
 
-	public get modelViewId(): string {
-		return this._model.modelViewId;
+	public get notebookUri(): URI {
+		return this._model.notebookUri;
+	}
+
+	public get providerId(): string {
+		return this._model.providerId;
 	}
 
 	public getTypeId(): string {