Add Debian package

[twpayne]

Is your feature request related to a problem? Please describe.

It would be great if chezmoi were included in Debian's packaging system as this would make chezmoi more easily installable for users of Debian-based distributions, particularly those in corporations who use Debian-based distributions but with strict IT departments who do not let users run non-allowlisted binaries on their machines.

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1012721 tracks the request for packaging in Debian.

Describe the solution you'd like

I'd like to be able to run

$ apt-get install chezmoi

on my Debian-based distribution and have it install chezmoi.

Describe alternatives you've considered

• Installing chezmoi via any of the existing installation methods.
• Using chezmoi archive to generate my dotfiles for my corporate-controlled machine (#1410).