Rename nodeType name in order to have file context menu in both mssql and SqlOpsStudio (#3862)

* Added data service context menu: file related operations. All new files are ported from SqlOpsStudio. Will remove these functionality from SqlOpsStudio.

* Used the existing constant hadoopKnoxEndpointName

* Rename nodeType name from hdfs to bdc. So we can have file context menu in both mssql and SqlOpsStudio. Need to add "Create External Table from CSV" support for bdc nodeType

* Rename bdc to mssqlcluster

extensions/mssql/src/prompts/prompt.ts

@@ -0,0 +1,33 @@
+'use strict';
+
+// This code is originally from https://github.com/DonJayamanne/bowerVSCode
+// License: https://github.com/DonJayamanne/bowerVSCode/blob/master/LICENSE
+
+import { InputBoxOptions, QuickPickOptions } from 'vscode';
+
+abstract class Prompt {
+
+	protected _question: any;
+	protected _ignoreFocusOut?: boolean;
+
+	constructor(question: any, ignoreFocusOut?: boolean) {
+		this._question = question;
+		this._ignoreFocusOut = ignoreFocusOut ? ignoreFocusOut : false;
+	}
+
+	public abstract render(): any;
+
+	protected get defaultQuickPickOptions(): QuickPickOptions {
+		return {
+			ignoreFocusOut: this._ignoreFocusOut
+		};
+	}
+
+	protected get defaultInputBoxOptions(): InputBoxOptions {
+		return {
+			ignoreFocusOut: this._ignoreFocusOut
+		};
+	}
+}
+
+export default Prompt;