Change from __file__ to inspect.getfile() syntax for path retrieval

[cosimolupo]

In the __main__.py file, in the lines retrieving the Cobrawap version from the VERSION file, path recognition has been implemented in a different way, moving from Path(__file__) to inspect.getfile(lambda: None) syntax, because of the former suspected to lead to a failure in readthedocs automatic checks triggered by commits in the NeuralEnsemble official Cobrawap repository. In the same way, again in the __main__.py file, also the syntax for retrieving pipeline_path has been changed accordingly, and simplified.

[mdenker]

Added details to understand this change for future reference: Readthedoc is throwing the following error:

[...]
      File "/home/docs/checkouts/readthedocs.org/user_builds/cobrawap/conda/89/lib/python3.11/site-packages/sphinxarg/ext.py", line 501, in run
        exec(code, mod)
      File "../../cobrawap/__main__.py", line 45, in <module>
        with open(Path(__file__).parents[1] / 'VERSION') as f:
                       ^^^^^^^^
    NameError: name '__file__' is not defined

Thus, it seems the current sphinx build uses an exec statement to execute parts of the code in main. Indeed, calling a string of code in exec, the __file__ attribute is not recognized.

exec("import inspect; print(__file__)")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in <module>
NameError: name '__file__' is not defined. Did you mean: '__name__'?

Thus, the suggested change is necessary for the doc build.