Use MonoProxy package for debugging

[captainsafia]

• Remove DebugProxy project
• Add references to MS.NETCore.BrowserDebugHost.Transport package
• Copy debugging proxy assemblies from package to Server project output
• Update path to executable in DebugProxyLauncher
• Update UseWebAssemblyDebugging middleware to pass browser query correctly to debuggers DevToolsHost configuration

Scenarios validated

• In-browser debugging
• Debugging from VS

[captainsafia]

@dotnet/aspnet-blazor-eng This is not ready to merge because there are still some packaging issues with the BrowserDebugHost. However, the framework-side changes are ready fro review.

[dougbu]

Is this a local change that bled into your PR❔ Version should match something actually coming out of the dotnet/runtime.

[captainsafia]

We're still working on getting a working package out of the runtime repo. There's been quite a few hiccups so I ended up using a dev build to unblock myself.

I marked this PR as ready for review so that the framework-side changes can be reviewed. I won't be merging it until we have a working package and will update the versions accordingly then.

[SteveSandersonMS]

It's extremely pleasing to see our code get simplified and so much of it be removed :) Awesome!

I know this isn't ready for merge until some external updates flow in, but the framework parts of the changes look solid.

[dougbu]

/fyi @captainsafia you can write a comment containing /azp run to get AzDO to do the same thing as closing and reopening the PR.

[captainsafia]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[Pilchie]

Approved for RC1.