Change database checker to no longer consider default fields required

[luisa-beerboom]

Closes #3020

TODO:

• What should be done about the fields that the database code is assuming are always filled (like organization/default_language)
• Remove the extra code from generate_models

[luisa-beerboom]

Closing bc PR is very old, will probably be hard to update and the lack of attention to the question in the issue may point to lack in necessity.
If this is still relevant, a new PR should be created.