Import option ADD_IGNORE_EXISTING should be removed

[marikaris]

How to Reproduce

The molgenis documentation states that here are four possible import actions: ADD/ADD_UPDATE_EXISTING/ADD_IGNORE_EXISTING/UPDATE. However, it also states ADD_IGNORE_EXISTING cannot be used in EMX and VCF only supports ADD. The only code that seem to use the ADD_IGNORE_EXISTING is a VCF import test, checking whether an error is thrown if you use it. Ontologies and amazon bucket ingest also don't use it. The documentation therefore is very confusing.

Expected behavior

ADD_IGNORE_EXISTING should be removed from the documentation, and possibly also from code because it isn't used and causes confusion everytime we stumble upon it

Observed behavior

ADD_IGNORE_EXISTING is causing confusion everywhere

[fdlk]

Or implemented perhaps?

[mswertz]

I think generally users don't want 'ignore existing' but prefer idempotent behavior. But indeed we should discuss how to handle this one.

[fdlk]

It got introduced for i18n data, where you want to import the defaults without overriding what's already been written by users