Host our own NuGet feed for packages that we need that aren't elsewhere yet (#1951)

* Stop hosting packages inside of here. Put them on a blob storage account instead.

NuGet.Config

@@ -5,7 +5,10 @@
         <!-- Add repositories here to the list of available repositories -->
         
         <!-- Dependencies that we must carry because they're not on public nuget feeds right now. -->
-        <add key="Static Package Dependencies" value="dep\packages" />
+        <!--<add key="Static Package Dependencies" value="dep\packages" />-->
+        
+        <!-- Use our own NuGet Feed -->
+        <add key="Windows Terminal NuGet Feed" value="https://terminalnuget.blob.core.windows.net/feed/index.json" />
         
         <!-- Internal NuGet feeds that may not be accessible outside Microsoft corporate network -->
         <!--<add key="TAEF - internal" value="https://microsoft.pkgs.visualstudio.com/DefaultCollection/_packaging/Taef/nuget/v3/index.json" />

dep/packages/README.md

@@ -1,7 +0,0 @@
-These packages are redistributed inside this folder because they are not yet available on a public NuGet feed.
-
-## Microsoft.UI.XAML
-This package is a custom development build fork to help us light up tab support. It will eventually go onto the same public feed as the existing `Microsoft.UI.XAML` package that's currently available on NuGet.org
-
-## TAEF.Redist.WLK
-This package is vetted for public redistribution and release, but the TAEF team hasn't set up a public feed to consume it yet. If/when they do, we'll move to that.