Add django jalali settings

[mobinghoveoud]

close #266

Description of Changes

• Added a settings class for accessing JALALI_SETTINGS in settings.py.
• Added ADMIN_JS_STATIC_FILES and ADMIN_CSS_STATIC_FILES settings.
• RefactoredAdminjDateWidget media handling.
• Added documentation for settings and defaults.

Testing

• Tested with Django 4.2
• Tested with Django 5.1

[hramezani]

Thanks @mobinghoveoud for this PR. please:

• Add some tests for JalaliSetting
• Document how to use JalaliSetting
• Add a changelog entry in https://github.com/slashmili/django-jalali/blob/main/CHANGELOG.md for the new feature.

[mobinghoveoud]

Thanks for your review, @hramezani.
The changes have been made. Let me know if there's anything else.

[hramezani]

Thanks @mobinghoveoud for the update. LGTM 👍

I approved the PR and waiting for @slashmili to check.

We can merge it in some days and prepare a new release

[slashmili]

Sorry for the late reply, I was away.

Nice work @mobinghoveoud!

Thanks @hramezani for reviewing it. I'd assume we just need to bump the minor?

[slashmili]

Released as 7.3.0