Also expose the awaiters to Microsoft.Test.Apex.VisualStudio

Fixes #12378

Expose a special CodeActionOperation so users can navigate to document positions as part of applying a code action.

various rename, code clean ups

* Make sure that we notify the workspace hosts when IWorkspaceProjectContext.LastDesignTimeBuildSucceeded is updated.

Fixes #14306

* Ensure that we create an external error reporter per-project ID in the CPSProjectFactory

Fixes #14329

* Fix build errors from prior refactoring

* Further simplify GetExternalErrorReporter

* Fix unit tests.

now all solution checksum data is moved down to solution states. and ISolutionSynchrnoizationService will only do synchrnoization between 2 hosts.