Upgrade EasyAuditMiddleware to support sync and async contexts.

[KaczuH]

EasyAuditMiddleware currently only supports synchronous code, requiring adaptations by Django for async operation.

As such, projects using easy audit cannot benefit from async stack as shown by the django.request logger:

DEBUG:django.request:Asynchronous handler adapted for middleware easyaudit.middleware.easyaudit.EasyAuditMiddleware.

Relevant Django documentation can be found in Django Docs:.

There is a potential simple fix: replacing threading.local with asgiref and using MiddlewareMixin.