Move code quality dependencies to separate environment

[albertomercurio]

Checklist

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• Please read Contributing to QuantumToolbox.jl.
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Description

Here I move the code quality dependencies (Aqua.jl and JET.jl) to a separate environment. In this way we simplify the dependency structure of the package, trying to make it compatible to the Julia nightly tests (that were failing due to JET).

This is different from the implementation we adopted months ago, where we were running Pkg.add(["Aqua", "JET"]) with an increase of run test times. Here I actually create a separate environment for that, which allows to have everything already precompiled.

I have also changed the order of the tests. I think that having the core tests first is better, since we are first interested in the actual working changes, and only after in improving the code quality.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.41%. Comparing base (9ca0815) to head (b63c19b).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #380   +/-   ##
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  Coverage   93.41%   93.41%           
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  Files          43       43           
  Lines        2809     2809           
=======================================
  Hits         2624     2624           
  Misses        185      185           

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