Added Django4.0 compatability

[JaisPiyush]

'django.utils.translation.ugettext_lazy' is removed since Django==4.0 in favour of 'django.utils.translation.gettext_lazy'. Added django version based conditional import of the following modules, making it backward compatible

[feavilan04]

Hi everybody, please update the version to be able to use it with Django 4.

Thanks in advance.

[jensenbox]

This PR is better than mine - maybe we could combine them somehow?

https://github.com/georgemarshall/django-cryptography/pull/66

Yours is better because it supports backwards compatibility.

[georgemarshall]

Duplicates efforts in #68