Description of problem:
How to remove rpm packages not more required/needed by satellite 6.15?

We have a system that has been steadily upgrading for over the last 4+ years from Satellite 6.11 to Satellite 6.15, thus there are left over packages from RedHat 7, several python versions (2,3.6,3.8,3.9,3.11 …).
Also we can see there are packages installed from Sat6.12, 6.13 and 6.14 repo.

python38-importlib-resources.noarch 5.0.0-3.el8pc @satellite-6.11-for-rhel-8-x86_64-rpms
python38-jsonschema.noarch 4.6.0-3.el8pc @satellite-6.11-for-rhel-8-x86_64-rpms
rubygem-rchardet.noarch 1.8.0-1.el8sat @satellite-6.12-for-rhel-8-x86_64-rpms
rubygem-redfish_client.noarch 0.5.4-1.el8sat @satellite-6.13-for-rhel-8-x86_64-rpms
rubygem-representable.noarch 3.2.0-1.el8sat @satellite-6.13-for-rhel-8-x86_64-rpms
rubygem-request_store.noarch 1.5.1-1.el8sat @satellite-6.15-for-rhel-8-x86_64-rpms
rubygem-responders.noarch 3.1.1-1.el8sat @satellite-6.15-for-rhel-8-x86_64-rpms
rubygem-rest-client.noarch 2.1.0-1.el8sat @satellite-6.13-for-rhel-8-x86_64-rpms
rubygem-roadie.noarch 5.1.0-1.el8sat @satellite-6.14-for-rhel-8-x86_64-rpms

Version-Release number of selected component (if applicable):
Satellite 6.15