Feature to audit log the changes along with old and new values.

[vivekshah1801]

Is your feature request related to a problem? Please describe.
We use extra-settings in our services. Since the access to change the settings is with multiple teammates, we want a way so that we can effectively manage the change in values. Currently django history shows which user has changed which field. Having the ability to log the change in value will be a good enhancement.

Describe the solution you'd like
Currently django logs the change as
April 20, 2023, 12:54 p.m. username (name) Changed value_bool.
What it should be
April 20, 2023, 12:54 p.m. username (name) Changed value_bool from <old_value> to <new_value>

Describe alternatives you've considered
We can do it in post_save signal and expose a configuration via settings to enable/disable.
We can also do it by overriding construct_change_message method.

Additional context

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[fabiocaccamo]

@vivekshah1801 I think that overriding construct_change_message is the best approach for achieving this.

Here a quick sketch:

from django.utils.text import get_text_list

# ...

    def construct_change_message(self, request, form, formsets, add=False):
        if add:
            return super().construct_change_message(request, form, formsets, add=add)
        
        change_message = []
        if form.changed_data:
            changes = []
            for field in form.changed_data:
                old_value = form.initial.get(field, _("<unknown>"))
                new_value = form.cleaned_data.get(field, _("<unknown>"))
                changes.append(f"{field} from {old_value} to {new_value}")
            change_message.append(f"Changed {get_text_list(changes, 'and')}.")
        return change_message

If you can test it on your side and submit a PR it would be great!