Move STJ code to Equinox

Author: ylibrach

Diff for: src/Equinox.Cosmos/Equinox.Cosmos.fsproj

@@ -10,10 +10,6 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <Compile Include="Json\JsonElementHelpers.fs" />
-    <Compile Include="Json\Utf8JsonReaderExtensions.fs" />
-    <Compile Include="Json\JsonRecordConverter.fs" />
-    <Compile Include="Json\Options.fs" />
     <Compile Include="..\Equinox.Core\Infrastructure.fs" Link="Infrastructure.fs" />
     <Compile Include="CosmosJsonSerializer.fs" />
     <Compile Include="Cosmos.fs" />

Diff for: src/Equinox.Cosmos/Json/JsonElementHelpers.fs

@@ -9,6 +9,10 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <Compile Include="Json\JsonElementHelpers.fs" />
+    <Compile Include="Json\Utf8JsonReaderExtensions.fs" />
+    <Compile Include="Json\JsonRecordConverter.fs" />
+    <Compile Include="Json\Options.fs" />
     <Compile Include="Flow.fs" />
     <Compile Include="Equinox.fs" />
   </ItemGroup>
@@ -20,6 +24,7 @@
     <PackageReference Include="FSharp.Core" Version="3.1.2.5" Condition=" '$(TargetFramework)' == 'net461' " />
     <PackageReference Include="FSharp.Core" Version="4.3.4" Condition=" '$(TargetFramework)' == 'netstandard2.0' " />
     <PackageReference Include="Serilog" Version="2.7.1" />
+    <PackageReference Include="System.Text.Json" Version="4.7.1" />
   </ItemGroup>
 
 </Project>