README an das Fachschaftsformat anpassen, Container automatisch bauen

See merge request !3

removed crontab in this branch because it will work with the internal tarball backup for now (backup.sh executed by minecraft server plugin essentialsX)

added cron for backup, needs to be adjustet to the time when the backup is started if other backuo solution is used (use case for external backuo suite like duplicati etc)

added wait for last launched background process to give the server time to shutdown

got it finally working ^^