Add datavirtualization extension (#21594)

* initial

* cleanup

* Add typings ref

* fix compile

* remove unused

* add missing

* another unused

* Use newer vscodetestcover

* newer dataprotocol

* format

* cleanup ignores

* fix out path

* fix entry point

* more cleanup

* Move into src folder

* Handle service client log messages

* remove unused

extensions/datavirtualization/src/test/mockFileSource.ts

@@ -0,0 +1,47 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as fs from 'fs';
+
+import { IFileSource, IFile } from '../fileSources';
+
+export class MockFileSource implements IFileSource {
+	filesToReturn: Map<string, IFile[]>;
+	constructor() {
+		this.filesToReturn = new Map<string, IFile[]>();
+	}
+	enumerateFiles(filePath: string): Promise<IFile[]> {
+		let files: IFile[] = this.filesToReturn.get(filePath);
+		return Promise.resolve(files);
+	}
+
+	mkdir(dirName: string, remoteBasePath: string): Promise<void> {
+		return Promise.resolve(undefined);
+	}
+
+	writeFile(localFile: IFile, remoteDir: string): Promise<string> {
+		return Promise.resolve(undefined);
+	}
+
+	delete(filePath: string): Promise<void> {
+		throw new Error('Method not implemented.');
+	}
+
+	readFile(filePath: string, maxBytes?: number): Promise<Buffer> {
+		throw new Error('Method not implemented.');
+	}
+
+	readFileLines(path: string, maxLines: number): Promise<Buffer> {
+		throw new Error("Method not implemented.");
+	}
+
+	createReadStream(filePath: string): fs.ReadStream {
+		throw new Error('Method not implemented.');
+	}
+
+	exists(filePath: string): Promise<boolean> {
+		throw new Error('Method not implemented.');
+	}
+}