Inline rename highlight color in Dark Theme only has a contrast ratio of 1.238:1, and the target is 1.5:1

Original Color: #A6F1A6
New Color: #D3F8D3

Contrast ratio is 1.485:1 with new color

Resolves: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1139737

This reverts commit f755e8a8. That
change meant our EditorFeatures code was using DllImports in the
cross-platform binary, and we weren't sure what that would do in
VS for Mac if that code ran. It also brought a dependency on
Microsoft.VisualStudio.RemoteControl, which also seems to depend on
various Windows specific APIs.

We'll finish up the decision of what to do in
https://github.com/dotnet/roslyn/pull/45115

* Move SymbolSearch down to EditorFeatures

* RemoteControl package reference

Fixes #44594

* RemoveHostClientProvider

* Do not start ServiceHub in command line mode

* Unused usings

* CreateConnection can no longer return null

* Connection refactoring

* Feedback

* Feedback

* Workaround for CodeLens issue

* Address NuGet PackageInstall failure

* Remove NuGet workaroud fixed in 15.9

* Fix potential hang

* Remove remote host restarting logic

* RemoteServiceName

* Remove dependency on Workspace

* Refactoring

* Fixes

This reverts commit 3ae0f796, reversing
changes made to a2ec364d.

Move DefinitionLocation declaration, add new parameters to GetConflictEditSpan and GetReferenceEditSpan