add debian/postfix version

ungleich-mail/Dockerfile-debian-postfix-only

@@ -0,0 +1,5 @@
+FROM debian:12.7
+
+RUN apt-get update && apt-get install -y postfix  &&  rm -rf /var/lib/apt/lists/*
+
+RUN postconf maillog_file=/dev/stdout

ungleich-mail/README.org

@@ -12,6 +12,7 @@
    - maybe later?
 ** PROGRESS Define where/how to save mails
    - /data would be fitting
+   - database as an option - that might require its own pvc
 ** PROGRESS Add db support (?) or not?
    - all file based could be very easy
    - restarts are usually fine