Add HsnTsnClient and related classes for vehicle data scraping

- Implement HsnTsnClient to fetch vehicle data from hsn-tsn.de
- Create VehicleDetail and HsnTsnVehicle classes for data representation
- Add CSV output functionality in Program.cs
- Include necessary NuGet packages in project file
- Add README with usage instructions

src/HsnTsnScraper/HsnTsnScraper.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="CsvHelper" Version="33.0.1" />
+    <PackageReference Include="HtmlAgilityPack" Version="1.11.71" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="8.0.1" />
+    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="8.0.10" />
+  </ItemGroup>
+
+</Project>