Update all dependencies

CNE is currently outdated with respect to:
* software dependencies (flake configuration)
* GHC version and associated tool (stuck to 9.6 to to plutus-tx requirements)
* cardano ecosystem libraries

Additionally, some other aspects are to be revamped:
* we no longer use fourmolu, replaced by ormolu, but there are remnants about it
* hpack should be used to get homogeneous .cabal files
* some pre-commit hooks need update (use of hpack, removal of cabal-fmt)
* some libraries, like freer-simple are no longer maintained and need to go

This entails the following initial tasks
- [x] update the flake.nix and flake.lock, using GHC 9.12 now supported by the plutus-tx plugin
- [x] add hpack in the dependencies, as a pre-commit hook, and create package.yaml files for each project
- [x] remove any reference to fourmolu
- [x] update cabal.project to account for new versions of dependencies, and align package.yaml files accordingly

From this initial update, more tasks will spawn, which will be set as sub-issues from this one.

Start by reviewing flake.nix, flake.lock, cabal.project, the package.yaml files, and the pre-commit configuration to identify which dependency and tooling tasks remain after the checked items. Check the related sub-issues for defined follow-up work, then verify that outdated libraries, hooks, and cabal files are addressed consistently.

Written by the indexing model from the issue text.