Django 4.x compatability

[htukiain]

With Django 4.1.1. the only error I have received is:

{% if message.recipient.pk == user.pk %} <a class="save btn btn-primary" href="{% url 'messages_reply' message.id %}">{% trans "Reply" %}</a> {% endif %}
I could make PR but unfortunately this repo seems to be unmaintained....

[arneb]

Feel free to make a PR. If it changes only the neccessary parts and is easy to review it might get merged. Thanks!

[htukiain]

Excellent! Here you are: #152

[frankystone]

just found there are some more incompatibilities:

• Django 4.0 removed translation features e.g. ugettext_lazy
• django.utils.encoding.python_2_unicode_compatible isn't available anymore since django 3.0

@arneb any chance to get this app up to date?

[alexclinky]

Any change to get this updated for Django 4.x