Add ReC.Infrastructure project to the solution

A new project, `ReC.Infrastructure`, has been added to the solution.
The project is configured to target `.NET 8.0` and includes modern
features such as implicit global usings and nullable reference types.
It has been integrated into the solution's build configurations
(Debug/Release for Any CPU) and nested under the `src` folder.

src/ReC.Infrastructure/ReC.Infrastructure.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>