Change installation guide to run as non-root user

Modern Linux distributions create users with administrative permissions. Login to the local system with user root via SSH or on the console is prevented for security reasons. With sudo an user can be granted with permissions to do administrative tasks. To follow best practices we should migrate our installation guide to use a non-root user with sudo permissions. The following policies are enforced for different distributions and should be reflected in our install guide:

• Debian 10: doesn't have sudo environment by default
• Ubuntu 20.04 LTS: only login console/SSH with user and sudo is available
• CentOS 7/8: only SSH login with user, root login only console, sudo is available
• RHEL 7/8: ???