Add a mechanism to be a customer of the extension host (share lifecycle) and begin reducing usage of IThreadService

clean up monaco.d.ts

* Add Type Definition Provider API

Adds a new API to support type definition providers and adds an initial type definition provider for TypeScript

* Fix comment

* Addressing comments

* Fixer menu option ordering

* Added simple test

* Rename TypeDefinitionProvider to TypeImeplementationProvider

**bug**
In #18346, I originally called the new go to implementation provider api `ImplementationProvider` which we then decided to rename to `TypeDefinitionProvider`. At the time, I didn't realize that a type definition was actually its own, unrelated concept.

**Fix**
Rename `TypeDefinitionProvider` to `TypeImplementationProvider` to make it clear what the purpose and use of this api is.

* Fix a few names in comments

* Add Go To Implementation Api

For #10806

Adds a new API for supporting  `go to implementation` command for languages. Implements an example for TS

* Rename

* Cleanup

debt - no guessing-caching, better use of gc-signals, command converter using gc-signals, main side heap service

* a declared module allows to have a sibling module containing experimental API
* this change also cleans up some bogous type pollution that happened because vscode used to be both, a declare module and a global namespace