Add whereByFields code / tests

- Add wrapper class for unnamed field parameters
- Support table qualifiers by field
- Support dot access to document fields/sub-fields

src/Tests.CSharp/BitBadger.Documents.Tests.CSharp.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>