Initial AD support for BDCs (#6741)

Partially working AD support for BDCs with some known issues
- Plumbed through kerberos support to Notebooks.
  - Using "gateway-0" for service temporarily as service endpoints API doesn't yet return correct DNS name. Will update in separate PR once available
- Plumbed kerberos auth to HDFS, Spark. Only partially working as we use same token on each call 
  - Will fix in separate PR, as this requires a refactor of WebHDFS library. Will need to either get new token every time or set a cookie, both of which require refactors
- Fixed error when Data Service node expansion failed and blocked all OE expansion
- Support for SqlToolsService change to use new cluster endpoints DMV
  -  Updated API to add new endpoints field to replace IP + port
  - Added logic to handle case where endpoints for Yarn, Grafana etc. are in the list
  - Sort list and use expected new localized strings

- Updated SqlToolsService to include support for new DMV
- Add "gateway-0" handling in Jupyter session as workaround for lack of domain names in endpoints list

extensions/notebook/src/common/utils.ts

@@ -141,4 +141,4 @@ export function isEditorTitleFree(title: string): boolean {
 	let hasTextDoc = vscode.workspace.textDocuments.findIndex(doc => doc.isUntitled && doc.fileName === title) > -1;
 	let hasNotebookDoc = azdata.nb.notebookDocuments.findIndex(doc => doc.isUntitled && doc.fileName === title) > -1;
 	return !hasTextDoc && !hasNotebookDoc;
-}
+}