refactor: standardize imports

[SMoraisAnsys]

Currently the project works by either importing specific classes or importing a module as alias and then using alias.MyClass.
However, this does not seem to be standardized in the repo as both approaches are used.

Would it be possible to standardize this by using direct class imports and not importing modules?

Note that this would require to change __init__.py files and other modules.

[SMoraisAnsys]

@pluAtAnsys Can we close this issue following your PR ?