Refactor Azure Core extension for easier resource addition (#7958)

Consolidated most logic into a base class and common resource request pattern.
Reduces cost to add new providers, which will help for SQL Managed Instance support

extensions/azurecore/src/azureResource/constants.ts

@@ -3,8 +3,6 @@
  *  Licensed under the Source EULA. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-'use strict';
-
 export enum AzureResourceItemType {
 	account = 'azure.resource.itemType.account',
 	subscription = 'azure.resource.itemType.subscription',
@@ -12,6 +10,7 @@ export enum AzureResourceItemType {
 	database = 'azure.resource.itemType.database',
 	databaseServerContainer = 'azure.resource.itemType.databaseServerContainer',
 	databaseServer = 'azure.resource.itemType.databaseServer',
+	sqlInstance = 'azure.resource.itemType.sqlInstance',
 	message = 'azure.resource.itemType.message'
 }
 
@@ -22,4 +21,4 @@ export enum AzureResourceServiceNames {
 	subscriptionService = 'AzureResourceSubscriptionService',
 	subscriptionFilterService = 'AzureResourceSubscriptionFilterService',
 	tenantService = 'AzureResourceTenantService'
-}
+}