Create Firewall Rule support with a simple Resource Provider implementation

Implementation of the resource provider APIs in order to support Create Firewall Rule. Provides definition for a ResourceProvider and Authentication service. The ResourceProvider supports firewall rules for now, and since authentication is routed through that method it will call into the auth service to set up the current account to be used.

Additional notes:
- Fixed deserialization by adding an Accept header. This shouldn't be necessary, but for some reason the firewall rule defaults to XML without this
- Use generic server list and parse the ID to get the resource group, avoiding a large number of extra calls for each RG
- Errors now include error message from the API

src/Microsoft.SqlTools.ResourceProvider/Microsoft.SqlTools.ResourceProvider.csproj

@@ -20,6 +20,11 @@
 
   <ItemGroup>
     <ProjectReference Include="..\Microsoft.SqlTools.Hosting\Microsoft.SqlTools.Hosting.csproj" />
+    <!-- Note: must reference the resource provider projects in order for them to be bundled into the app. Otherwise will not have any of the required DLLs and
+      dependencies included when the project is shipped. If adding new DLLs, add them here or find another solution to keep them bundled
+    -->
+    <ProjectReference Include="..\Microsoft.SqlTools.ResourceProvider.Core\Microsoft.SqlTools.ResourceProvider.Core.csproj" />
+    <ProjectReference Include="..\Microsoft.SqlTools.ResourceProvider.DefaultImpl\Microsoft.SqlTools.ResourceProvider.DefaultImpl.csproj" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="Localization\sr.resx" />