Clean up Razor initialization in VS Code

[davidwengier]

In dotnet/vscode-csharp#6473 changes were made to not wait for the user to open a Razor file in order to initialize Razor. This works, but there are still other pieces of code in Roslyn, Razor and the C# extension, that support the previous delayed initialization. We can/should review the other code and see if there is more we can do to streamline things, now that we're not delaying. eg, do we need the razor/initialize LSP method at all?

[davidwengier]

Going to close this out, as this area has changed significantly (we have named pipes now!)