[ENH]: Reorder all utilities and tests

Describe the feature you want to add to this project

• I noticed we have pycaret\internal\pycaret_experiment\utils.py, pycaret/internal/utils.py and pycaret/utils. We should move everything to pycaret/utils imo.
• We have pycaret/tests and pycaret/internal/tests. Not sure what the latter does. Can it be moved/removed?
• I suggest to move the whole tests directory outside of the code base. Leave it in the root folder. I think this is best practice.

Let me know your thoughts.

Describe your proposed solution

..

Describe alternatives you've considered, if relevant

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Additional context

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• We have pycaret/tests and pycaret/internal/tests. Not sure what the latter does. Can it be moved/removed?

pycaret/internal/tests refers to statistical tests used in the code and modeling building process. That is different from pycaret/tests which are the unit tests. As such, the statistical tests should not be changed/altered in my opinion.

I noticed we have pycaret\internal\pycaret_experiment\utils.py, pycaret/internal/utils.py and pycaret/utils. We should move everything to pycaret/utils imo.

I noticed the same thing when developing time series. I started consolidating any new utils that I was developing into pycaret/utils. I agree, we need to consolidate old/legacy utils into this module as well.

I suggest to move the whole tests directory outside of the code base. Leave it in the root folder. I think this is best practice.

I am ok with this.