multiprocessing RunitimeError for Windows

[fjribi]

PR concerning errors like ("NameError: name 'np' is not defined") when using multiprocess exec mode on windows:
Linked to #104 & #93

Is it convenient to add the following "workaround code" to \cadCAD_init_.py file to fixe the issue?

name = "cadCAD"
configs = []

#added code
import os
if os.name == 'nt': 
    import dill
    dill.settings['recurse'] = True 
This fixed the issue.

or should we only add the code to \cadCAD\engine_init_.py] file to fixe the issue?

class ExecutionContext:
    def __init__(self, context: str = ExecutionMode.multi_proc) -> None:
...
        elif context == 'multi_proc':
           #add code here? 
           import os
           if os.name == 'nt': 
               import dill
               dill.settings['recurse'] = True 
            self.method = parallelize_simulations

to limit the setting to multiprocess exec mode and reduce potential side effects. Indeed, although this seems to be a stable workaround for windows, there are some comments (see [https://github.com/uqfoundation/dill/issues/115]) that are mitigated about the solution.

There are 2 other less convincing alternatives for our issue:
1 - To declare the missing global variables (which are not correctly serialized without dill.settings['recurse'] = True) at the function level (see [https://github.com/uqfoundation/multiprocess/issues/6]) => could be less practical, since this requires to re-declare global variables locally...
2 - to use cloudpickle instead of dill (see [https://github.com/apache/airflow/issues/7870]), => no idea on the impact of the migration

Regards,

[JEJodesty]

@fjribi
Thanks for your contribution!
Replacing location of your change to cadCAD/__init__.py post merge

[fjribi]

Ok, thanks