Jenkins should not have dev packages installed by default
This behaviour hide a critical bug when 20.05.00 was released (https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=28616). A use of Data::Printer was introduced, it's not a Koha dependency but is installed by koha-testing-docker, developers didn't notice the problem neither Jenkins.
I am suggesting to
- add a CI or dev_instance flag in ktd config
- remove those dependencies from Dockerfile
- install them on run
- add a CI or dev_instance flag in ktd config
- keep those dependencies from Dockerfile
- remove them when run on CI
Both are ugly, suggestions welcomed!