Coverage for the DAM connector feature (unsplash: https://github.com/ibexa/connector-unsplash, https://github.com/ibexa/connector-unsplash)

To be covered:
1) "Select from DAM" action for ezimageasset fieldtype

This additionaly requires:
1) Setting up CI in the unsplash repository
2) Setup step for Unsplash (adding the required yaml config)
3) Triggering the CI every day from the ibexa/oss repo ("nightly" workflow)

This job cannot be part of the normal regression runs, because unsplash is not present out of the box