CH-167 Async support on Django user attach middleware

[filippomc]

Closes CH-167

Implemented solution

Changed the middleware to conform with this: https://docs.djangoproject.com/en/5.1/topics/http/middleware/#async-middleware

Refactored most of the code related to users sync to use asyncio apis

How to test this PR

Run any django based application using this branch (I have tested it locally on a django Ninja app)

Sanity checks:

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• In this PR it is explicitly stated how to test the current change
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Breaking changes (select one):

• The present changes do not change the preexisting api in any way
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Test coverage (select one):

• Tests for the relevant cases are included in this pr
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Documentation (select one):

• The documentation has been updated to match the current changes
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• Screenshots of the changes
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