debian: add user to sudo group

[practicalli-johnny]

Debian recommends using the root account for all system administration, rather than sudo.

Installing some applications, like docker desktop, work better when installing from a standard user account that has sudo elevated privileges.

https://wiki.debian.org/sudo/

[practicalli-johnny]

The Debian sudo page if fairly long and does not have a heading link anchor to the relevant section to adding a user to the sudo group.

Add the actual command on the Debian Linux page for Practicalli Engineering Playbook for convenience

sudo adduser foo -G sudo