Added dockerfile

src/KpiGenerator/Dockerfile

+FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build-env
+WORKDIR /App
+
+# Copy everything
+COPY . ./
+
+# Add nuget sources for private packages (here: api-client)
+RUN dotnet nuget add source "https://git.rwth-aachen.de/api/v4/projects/88930/packages/nuget/index.json" -n "api-client"
+
+# Restore as distinct layers
+RUN dotnet restore
+
+# Build and publish a release
+RUN dotnet publish -c Release -o out
+
+# Build runtime image
+FROM mcr.microsoft.com/dotnet/aspnet:8.0
+
+# Install cron and other necessary packages
+RUN apt-get update && \
+    apt-get install -y cron && \
+    apt-get clean
+
+WORKDIR /App
+COPY --from=build-env /App/out .
+
+# Set the build-time argument and default environment variable
+ENV DOTNET_ENVIRONMENT=Development
+
+# Create the log file
+RUN touch /var/log/cron.log
+
+ENTRYPOINT /bin/sh -c "/App/Coscine.KpiGenerator all"
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