Read from stdin, write to stdout

[Rossojo]

The following changes were necessary, to use a docker image to apply the mods:

• The input file can be read from stdin by using '-' as input filename
• The output file can be written to stdout by using '-' as output filename

Given a docker image this allows to apply the mods even without python installed:

cat /path/to/your/empires2_x2_p1.dat | docker run -i --rm ghcr.io/Rossojo/aoe2-auto-mods:latest - - --mods random-costs > /path/to/output/empires2_x2_p1.dat

I am not happy about handling decompression and compression in the auto-mod.py. I just copied the relevant parts from the genieutils package, as that package does not offer a function to retrieve compressed bytes.