RemoteUserAuthentication, docs, and tests

> keeps you error messages

to

> keeps your error messages

and 

> more cleanly separated from your code

to 

> cleaner and more separated from your code

The blog post referenced in the documentation has been since moved to a new location.

* Add regression test for #2505. Thanks @pySilver!

* Add regression test for #5087

* Revert "Cached the field's root and context property."

This reverts commit 79200580.

* Removed Micropyramid as a sponsor

* Changed monthly report link

Added the django user model

Accidentally also deleted a line.

So it is possible to copy paste the example and it will work out of the box.

typo: may -> many

Fix SearchFilter to-many behavior/performance

Ensure closables on `.FILES` get closed.

Sanitize serializer.data to remove hidden fields before rendering template JSON instance to raw data form.

* Fix lint issues

Raise validation error on invalid timezone parsing.

Add Django manage command to create a DRF user Token

Fix API documentation templates do not check for user authentication #5162

Fixed tests on Windows. Added unicode support to SlugField

Fixed #5228 Set ViewSet args/kwargs/request before dispatch

Add information in docs about djangorestframework-simplejwt package

Updated monthly report link

Link in the home page is broken

The link to the Python Exception Handling Techniques article written by Doug Hellmann is broken.

I could find the article in the URL I proposed.

typo fix