feat: make sysadmin dashboard org aware and implement course access r…

[andrey-canon]

Description

This update includes the following changes:

1. Make the sysadmin panel tenant-aware (courses are now displayed based on the course_org_filter value).
2. Allow access to the sysadmin panel based on the user's course access role.

Migration pr of #3

Issue # 1296

How to test

1. Set the course_org_filter with the right organization
2. Set the course access role for a non admin user
   
3. Go to /sysadmin and check the courses sections with and admin user a non admin user

Before

After

[johanseto]

LGTM

Working in my local env

org_aware_filter

Screencast.from.02-12-25.09.28.18.webm

course_access_role

Screencast.from.02-12-25.16.31.52.webm

[johanseto]

@andrey-canon Do you know why black is failing in the tests?
https://github.com/nelc/edx-sysadmin/actions/runs/19838627455/job/56841803054?pr=6#step:5:14https://github.com/nelc/edx-sysadmin/actions/runs/19838627455/job/56841803054?pr=6#step:5:14