Closes #41260

This reverts commit 646489a3.

This reverts commit 9ef11ce3bcd1ddd60391060962158c2f79215170.

* Build color schemes into pkgdef resources

* Add files to read items from PKGDEF files

* Apply ColorScheme PKGDEF as defaults colors

* Add ColorScheme dropdown to Advanced Options page

* Update formatting for contributed PkgDef files

* Add margin to custom theme warning

* Address ColorApplier feedback

* Updated based on PR feedback

* Change to a VsixColorCompiler package that includes VC runtime

* Remove VsixColorCompiler

* Move native methods

* Remove PKGDEF reading

* Add additional color options to ColorSchemeOptions

* Add color scheme reader for reading the scheme XML

* Add coverter for turning color schemed into registry entries

* Update applier to read schemes from xml

* Initialize applier on package load

* Update option pages to refresh onLoad

* Remove VsixColorCompiler PackageReference

* Implement feedback from Code Review

* More feedback from Code Review

* Update file headers

* WIP

* Resolve PR feedback

* Use SchemeName in place of name strings

* Fix options persistence

* Make OptionChanged event nullable

* Revert change to GlobalOptionService

* Revert to using VisualStudioWorkspace for accessingOptions

* Clean up string resources, use Arcade resx generator

* CodeLens resources


* Use NET20 instead of NETFX20

Extracts out the changes to core Workspace changes from https://github.com/dotnet/roslyn/pull/41363.

* Add TypeScript external access APIs

* Make IVSTypeScriptDiagnosticAnalyzerImplementation optional.

* Add wrappers for ContainedDocument and ContainedLanguage