Do not install dependencies as those are no longer maintained.
Instead use the shell to set path to local installed version and miss
use nix-shell to build an environment that works for me for now.
Remove flakes for now.
I will use shells for now to not have a mixed setup.
Add composer v1 for a single customer project as overlay due to usage in
shell instead of flakes.
Adjust folder to not have unnecessary deep structure.
Add shell for reuter monorepo using composer v1.
Daniel Siepmann