Move to new implementation of Descriptors and Parameters

[andped10]

Required clean when moving to the new structure of Descriptors and Parameters.

First we need to confirm that the new descriptors a parameters are working in:

• EasyDiffraction
• EasyReflectometry (https://github.com/EasyScience/EasyReflectometryLib/tree/easyscience-new-fitting-and-parameter)

To clean the code base:

search for

• .Variable import Descriptor and delete
• .Variable import Parameter and delete

delete legacy tests:

• tests/integration_tests/Fitting/test_fitter_legacy_parameter.py
• tests/integration_tests/Fitting/test_multi_fitter_legacy_parameter.py
• tests/unit_tests/Fitting/test_constraints_legacy_parameter.py

rename folder: new_variable -> variable

Following files should be cleaned:

• pyproject.toml, pint is no longer a requirement
• src/easyscience/Objects/Inferface.py, clean up TODO sections
• src/easyscience/Objects/ObjectClasses.py, clean up TODO sections
• src/easyscience/fitting/Constraints.py, clean up TODO sections
• src/easyscience/fitting/minimizers/minimizer_bumps.py, clean up TODO sections
• src/easyscience/fitting/minimizers/minimizer_lmfit.py, clean up TODO sections
• tests/unit_tests/Fitting/test_constraints_legacy_parameter.py, delete
  -tests/unit_tests/Objects/new_variable/test_descriptor_from_legacy.py, rename
• tests/unit_tests/Objects/new_variable/test_parameter_from_legacy.py, rename

Probably able to move to numpy 2

[henrikjacobsenfys]

Completed in #94
We still need to check and update EasyDiffraction and EasyCrystallography.