- Create a simple workspace context service for standalone editor
- Use the test context service for tests

From: https://github.com/Microsoft/TypeScript/issues/15352

TS 2.3.1 introduced a breaking change by [switching to covariant types for callbacks](https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#covariance-in-callback-parameters). This change tries to fix these compiler errors in the workbench codebase

- Use uuids along with names to sync with gallery until market place team fixes the query issue

-  id is pub.name. name in lower case.
- use id to match sync installed extension with gallery extension
- use id to identify extension while installing and uninstalling
- Clean up
- Remove IExtensionIdentity
- Add util methods to create gallery id and local extension id

related to #15558

related to #15259