feat: add setting configuration for relationships

[johanseto]

Description

This add the possibility to configure the course_overview mapping and user mapping via django settings using
COURSE_EXPERIENCE_SETTINGS
Know you can configure the relationship extra field via settings in tenant config.

"COURSE_EXPERIENCE_SETTINGS": {
    "COURSE_OVERVIEW_EXTRA_FIELD_MAPPING": {
        "ultra_name": "courseultra",
        "course_key": "instance__field"
    },
    "USER_EXTRA_FIELD_MAPPING": {
        "mega_name": "userultra",
        "user_key": "user__field"
    }
}

Testing instructions

Clone repo and add variable keys to configure course_experience_keys for relationship in tenant config as above.

After

Additional information

related jira story:
https://edunext.atlassian.net/jira/software/c/projects/FUTUREX/boards/36?modal=detail&selectedIssue=FUTUREX-459

Checklist for Merge

• Tested in a remote environment
• Updated documentation
• Rebased master/main
• Squashed commits