Legacy code duplication (Old Autosubmit class)

It seems that when the API was created, some files were copied from the autosubmit package to reutilize its code causing compatibility issues.

A clear case of this is in the autosubmit_api/database/autosubmit.py and autosubmit_api/autosubmit_legacy/autosubmit.py that have a copy of an old Autosubmit class. Until now I found this being called in:

• autosubmit_api/workers/business/populate_times.py (used by one worker)
• autosubmit_api/experiment/common_requests.py (used for the graph and tree view)
• autosubmit_api/statistics/test.py (for testing the statistics module) (to be removed as there is going to be a new pytest module)

With @bdepaula we guess that, if reutilization of the code is needed, we may import the needed helper functions from the autosubmitconfigparser or from the version of the autosubmit package that the user has installed as a solution of this.