Simplify dockerfile

DiscordChatExporter.Cli.dockerfile

@@ -0,0 +1,18 @@
+# Build
+FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
+
+COPY favicon.ico ./
+COPY NuGet.config ./
+COPY Directory.Build.props ./
+COPY DiscordChatExporter.Core ./DiscordChatExporter.Core
+COPY DiscordChatExporter.Cli ./DiscordChatExporter.Cli
+
+RUN dotnet publish DiscordChatExporter.Cli -c Release -o ./publish
+
+# Run
+FROM mcr.microsoft.com/dotnet/runtime:6.0 AS run
+
+COPY --from=build ./publish ./
+
+WORKDIR ./out
+ENTRYPOINT ["dotnet", "/DiscordChatExporter.Cli.dll"]