SignalR: Fix Crankier build

[staff0rd]

Fixes Crankier & BenchMarkServer builds.

A couple of questions;

1. Why were the projects dropped from SignalR.sln? (Fix SignalR build from VS #8492)
2. In Use NuGet.Config for SignalR benchmarks #9958 I see a note from @sebastienros that says we don't want to inherit Directory.Build.props, but both .csproj are using Reference.

[staff0rd]

@BrennanConroy can you please review this again? I've closed #9264 and will instead move that functionality to Crankier as suggested. This PR now represents moving the Directory* stuff so it only affects the benchmark server and the IHostingEnvironment deprecation update.

[BrennanConroy]

Thanks for the PR!