Loading medibase and icd11 static json and migrations

[DraKen0009]

Proposed Changes

1.Updated medibase.json

• removed _id field
• added id field

2.Updated MedibaseMedicine model , removed external_id

3.Updated python manage.py load_redis_index command to directly use the json to populate the redis

4.Migrate all related models to use id as fk instead of external_id

Associated Issue

• Fixes #1817
• Fixes #2003

Merge Checklist

• [x] Tests added/fixed
• [x] Linting Complete

Only PR's with test cases included and passing lint and test pipelines will be reviewed

@coronasafe/care-backend-maintainers @coronasafe/care-backend-admins