Remove vulnerable nuget package sources

NuGet.Config

@@ -1,10 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <packageSources>
-    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
-    <add key="Local" value="tools/LocalNugetFeed" />
+    <clear />
+    <!-- Do not add any additional feeds if new packages are needed they need to come from nuget.org or our azure-sdk-for-net DevOps feed -->
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+    <add key="azure-sdk-for-net" value="https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-sdk-for-net/nuget/v3/index.json" />
+
+    <!--
+      Used for azure-sdk-tools repo until issue https://github.com/Azure/azure-sdk-tools/issues/1329 is addressed
+    -->
     <add key="azure-sdk-tools" value="https://azuresdkartifacts.blob.core.windows.net/azure-sdk-tools/index.json" />
-    <add key="azure-sdk-for-net" value="https://azuresdkartifacts.blob.core.windows.net/azure-sdk-for-net/index.json" />
-    <add key="dotnet-tools" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/index.json" />
   </packageSources>
+  <disabledPackageSources>
+    <clear />
+  </disabledPackageSources>
 </configuration>