WIP - Add VirtualDDNSRouter.Client project with Docker support, YAML settings handling, and example configuration

VirtualDDNSRouter.Client/Dockerfile

@@ -0,0 +1,21 @@
+FROM mcr.microsoft.com/dotnet/runtime:10.0 AS base
+USER $APP_UID
+WORKDIR /app
+
+FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
+ARG BUILD_CONFIGURATION=Release
+WORKDIR /src
+COPY ["VirtualDDNSRouter.Client/VirtualDDNSRouter.Client.csproj", "VirtualDDNSRouter.Client/"]
+RUN dotnet restore "VirtualDDNSRouter.Client/VirtualDDNSRouter.Client.csproj"
+COPY . .
+WORKDIR "/src/VirtualDDNSRouter.Client"
+RUN dotnet build "./VirtualDDNSRouter.Client.csproj" -c $BUILD_CONFIGURATION -o /app/build
+
+FROM build AS publish
+ARG BUILD_CONFIGURATION=Release
+RUN dotnet publish "./VirtualDDNSRouter.Client.csproj" -c $BUILD_CONFIGURATION -o /app/publish /p:UseAppHost=false
+
+FROM base AS final
+WORKDIR /app
+COPY --from=publish /app/publish .
+ENTRYPOINT ["dotnet", "VirtualDDNSRouter.Client.dll"]