Fix PyInstaller issues

[arossert]

Following the discussion in #891, This PR is listing the modules directly from the filesystem.

According to this thread #1905, PyInstaller is not supporting the pkgutil.iter_modules so the dynamic module loading is not working.

I have added a code to list the modules directly from the source code that needs to be included in the bundle for this to work.
It is using a small PyInstaller hook to fetch the providers source files:

from PyInstaller.utils.hooks import collect_submodules, collect_data_files

hiddenimports = collect_submodules('faker.providers')
datas = (collect_data_files('text_unidecode') +
         collect_data_files('faker.providers', include_py_files=True))

If this PR will be approved, I will submit a PR in PyInstaller to include this hook.

It is not working for me using cx_freeze, I have no experience with it and I could not get it to work, always give me an exception:

ImportError: No module named providers

From a small test, it seems that pkgutil.iter_modules is working in cx_freeze but I still got this error (even when I try to explicitly include the module).

I think that it will be better to find a generic way for all the "code freezers" work but not sure that it is possible.

[fcurella]

Thank you @arossert

I wouldn't worry too much about cx_freeze. From what I see, your change should be fully backward compatible.

[arossert]

Thanks, do you know when the next version with this fix will be released?