Remove CredentialsService & keytar (#192224)

* Remove CredentialsService & keytar

ref https://github.com/microsoft/vscode/issues/115215
fixes https://github.com/microsoft/vscode/issues/143395

* compile

* remove imports

* rip the bandaid

extensions/microsoft-authentication/extension.webpack.config.js

@@ -12,9 +12,6 @@ const withDefaults = require('../shared.webpack.config');
 module.exports = withDefaults({
 	context: __dirname,
 	entry: {
-		extension: './src/extension.ts',
-	},
-	externals: {
-		'keytar': 'commonjs keytar'
+		extension: './src/extension.ts'
 	}
 });