Dependency update / fixes / skrungle bungle (#23745)

* Give .props files 2-space indents.

* Move to Central Package Management.

Allows us to store NuGet package versions all in one place. Yay!

* Update NuGet packages and fix code for changes.

Notable:

Changes to ILVerify.
Npgsql doesn't need hacks for inet anymore, now we need hacks to make the old code work with this new reality.
NUnit's analyzers are already complaining and I didn't even update it to 4.x yet.
TerraFX changed to GetLastSystemError so error handling had to be changed.
Buncha APIs have more NRT annotations.

* Remove dotnet-eng NuGet package source.

I genuinely don't know what this was for, and Central Package Management starts throwing warnings about it, so YEET.

* Remove Robust.Physics project.

Never used.

* Remove erroneous NVorbis reference.

Should be VorbisPizza and otherwise wasn't used.

* Sandbox fixes

* Remove unused unit test package references.

Castle.Core and NUnit.ConsoleRunner.

* Update NUnit to 4.0.1

This requires replacing all the old assertion methods because they removed them 🥲

* Oh so that's what dotnet-eng was used for. Yeah ok that makes sense.

* Add Robust.Analyzers.Test

* Update submodule

* commit to re-run CI

Content.IntegrationTests/PoolManager.cs

@@ -337,10 +337,10 @@ public static partial class PoolManager
         {
             // If the _poolFailureReason is not null, we can assume at least one test failed.
             // So we say inconclusive so we don't add more failed tests to search through.
-            Assert.Inconclusive(@"
+            Assert.Inconclusive(@$"
 In a different test, the pool manager had an exception when trying to create a server/client pair.
 Instead of risking that the pool manager will fail at creating a server/client pairs for every single test,
-we are just going to end this here to save a lot of time. This is the exception that started this:\n {0}", _poolFailureReason);
+we are just going to end this here to save a lot of time. This is the exception that started this:\n {_poolFailureReason}");
         }
 
         if (_dead)