Base image for build containers

Based on Debian Buster

Contains additionally:

• make
• openssh-client
• git
• python with the modules requests, pycodestyle and yaml
• gpg
• apt-transport-https
• wget and curl
• zip, unzip and 7z
• vim.tiny
• texlive
• GitLab release tool: https://home.hottis.de/gitlab/wolutator/gitlabreleaseuploader including validator for semantic version according to https://semver.org/