Add parent attributes to full export

[jochenklar]

This PR adds all parent attributes to the full export feature.

[MyPyDavid]

PR number 1000 🎉

[MyPyDavid]

do you not want to have any tests for this?
For example in here:

rdmo/rdmo/questions/tests/test_viewset_catalog.py

Line 241 in dd3cb84

def test_detail_export(db, client, username, password, export_format):

?

[jochenklar]

I mean, there is a test, right? We could test that everything is there though.

[MyPyDavid]

yes a general test is there, I mean testing for the specific content of the exported xml (which attributes should be in there..)

[jochenklar]

I added some tests.

[MyPyDavid]

thanks!