Since the default tag helper provider is used by MVC then MVC should
include it. Now that Blazor is in the mix we shouldn't include it for
all configurations.
Step 1: Add HostProject
This is a somewhat complex addition to the ProjectSnapshotManager. Now
that we accept updates from the underlying IDE project system we need to
coordinate those with the Workspace.
This means that ProjectSnapshot itself now also has a version concept.
Step 2: Introduce a new project system based on CPS
We use project capabilities defined by the Razor SDK to determine
whether to rely on MSBuild evaluation to detect the configuration or
whether to fallback to assembly-based detection.
Step 3: Flow RazorConfiguration everywhere
We use now expose the RazorConfiguration to the language service and
editor. This means that we no longer need to detect the project's
configuration asynchronously, it happens much faster now.
Ryan Nowak
Nate McMaster