Feat/model backed ui (#1145)

This is an initial PR for a new model-driven UI where extensions can provide definitions of the components & how they're laid out using Containers.
#1140, #1141, #1142, #1143 and #1144 are all tracking additional work needed to improve the initial implementation and fix some issues with the implementation.

Features:
- Supports defining a FlexContainer that maps to a flexbox-based layout.
- Supports creating a card component, which is a key-value pair based control that will lay out simple information to a user. Eventually this will have an optional set of actions associated with it.
- Has a sample project which shows how to use the API and was used for verification

src/sql/services/dashboard/common/dashboardViewService.ts

@@ -0,0 +1,31 @@
+/*---------------------------------------------------------------------------------------------
+ *  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 { createDecorator } from 'vs/platform/instantiation/common/instantiation';
+import Event from 'vs/base/common/event';
+
+import * as sqlops from 'sqlops';
+import { IItemConfig, IComponentShape } from 'sql/workbench/api/common/sqlExtHostTypes';
+import { IView, IModelView } from 'sql/services/model/modelViewService';
+
+export const SERVICE_ID = 'dashboardViewService';
+
+export interface IDashboardWebview extends IView {
+	setHtml(html: string): void;
+	onMessage: Event<string>;
+	sendMessage(message: string);
+}
+
+export interface IDashboardViewService {
+	_serviceBrand: any;
+	onRegisteredWebview: Event<IDashboardWebview>;
+	registerWebview(widget: IDashboardWebview);
+	onRegisteredModelView: Event<IModelView>;
+	registerModelView(widget: IModelView);
+}
+
+export const IDashboardViewService = createDecorator<IDashboardViewService>(SERVICE_ID);

src/sql/services/dashboard/common/dashboardViewServiceImpl.ts

@@ -0,0 +1,28 @@
+/*---------------------------------------------------------------------------------------------
+ *  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 { IDashboardViewService, IDashboardWebview } from 'sql/services/dashboard/common/dashboardViewService';
+import Event, { Emitter } from 'vs/base/common/event';
+import { IModelView } from 'sql/services/model/modelViewService';
+
+export class DashboardViewService implements IDashboardViewService {
+	_serviceBrand: any;
+
+	private _onRegisteredWebview = new Emitter<IDashboardWebview>();
+	public readonly onRegisteredWebview: Event<IDashboardWebview> = this._onRegisteredWebview.event;
+
+	private _onRegisteredModelView = new Emitter<IModelView>();
+	public readonly onRegisteredModelView: Event<IModelView> = this._onRegisteredModelView.event;
+
+	public registerWebview(widget: IDashboardWebview) {
+		this._onRegisteredWebview.fire(widget);
+	}
+
+	registerModelView(view: IModelView) {
+		this._onRegisteredModelView.fire(view);
+	}
+}