feat: Updates to .NET 6 (#843)

* Fixes an issue with moving directories across volumes
* Removes usages of WebClient
* Removes usages of Cryptographic Providers

Note: Even though .NET 6 introduces Xoshiro RNG, there is no way to control the seed. I'll do some reconciliation of Xoshiro so it functions closer to the built in one. For the most part, it has parity though.
Benchmarks show there is nothing odd about the implementations, they are within 1ns of each other.

azure-pipelines.yml

@@ -18,7 +18,12 @@ jobs:
     displayName: 'Install .NET 5'
     inputs:
       packageType: sdk
-      version: 5.0.401
+      version: 5.0.403
+  - task: UseDotNet@2
+    displayName: 'Install .NET 6'
+    inputs:
+      packageType: sdk
+      version: 6.0.100
   - task: NuGetAuthenticate@0
   - script: ./publish.cmd Release win
     displayName: 'Build'
@@ -62,7 +67,12 @@ jobs:
     displayName: 'Install .NET 5'
     inputs:
       packageType: sdk
-      version: 5.0.401
+      version: 5.0.403
+  - task: UseDotNet@2
+    displayName: 'Install .NET 6'
+    inputs:
+      packageType: sdk
+      version: 6.0.100
   - task: NuGetAuthenticate@0
   - script: ./publish.cmd Release $(os)
     displayName: 'Build'