Reduce size of v4 minimal image

[git-developer]

(Migrated from #115)

This is a request to reduce the size of the v4 minimal image.

The minimal image has grown significantly between v3 and v4:

$ docker images | grep fhem
ghcr.io/fhem/fhem-minimal-docker   3.3.1-bullseye                       c9b1f0c873e7   4 months ago    635MB
ghcr.io/fhem/fhem-minimal-docker   dev-bullseye                         cf28244b08a3   12 hours ago    905MB

Maybe a switch to the slim base image helps (not verified).

$ docker image ls | grep perl
perl                 5.36.3-slim-bullseye   52a305760451   3 weeks ago     132MB
perl                 5.36.3-bullseye        61325f916a7e   3 weeks ago     692MB

[sidey79]

Maybe this ist possible, during Installation of CPAN modules they need some build tools.

We can try to copy all cpan modules later to a slim based image layer. But first goal ist to get rid of some build bugs.

[git-developer]

$ docker image ls | grep fhem
ghcr.io/fhem/fhem-minimal-docker   dev-bullseye                         e9e2497c9e17   7 hours ago      531MB
ghcr.io/fhem/fhem-minimal-docker   3.3.1-bullseye                       c9b1f0c873e7   5 months ago     635MB

Thanks a lot!