Python modules inside of Arches Applications are not imported

[johnatawnclementawn]

Python modules inside of Arches Applications should be added to the path so they can be used.

I'm building an ETL module for the Arches RDM application, and was experiencing an issue in which the ETL module that I wrote, which lived in the application directory rather than the core directory, was not being imported. The issue presented itself here.

[jacobtylerwalls]

Bothered Johnathan about this briefly. We had trouble reproducing the issue so long as we had arches_rdm.etl_modules included in settings.ETL_MODULE_LOCATIONS.

The proposal that you shouldn't have to do that is captured in #10288.

[johnatawnclementawn]

Can be fixed by ensuring arches_rdm.etl_modules is appended to ETL_MODULE_LOCATIONS in settings.py