On step closer to 1.0.0

Over the past 10 months, RDE has absorbed various upgrades and
improvements:
- new features (distrobox, podman, prolog, sourcehut, android ...)
- and updated old ones (zsh, sway, mail, emacs, org-agenda ...)
- cloud image
- transitive package management for Elixir
- updated example configurations
- and more...

This release is halfway to 1.0.0

It contains all the needed tooling for semi-minimalistic working environment,
and have the first releases of guile-ares-rs and emacs-arei projects included.

It has new notification center and integrations for it, also added support for
the following programming languages:
- Python
- OCaml
- Common Lisp

After guix core-update rde release.

With slightly newer software, better designed, polished and new rde features,
and API improvements, a bit better example config structure.

doc: getting-started: Update timezone related info.

Moving to guix

Add a tag to reference from nix build