utils/build-galaxy-release.sh: Do not create duplicates for role plugins

This change reduces the size of the Ansible collection and removes unused
files.

While creating the collection, the role plugins have been linked into the
global plugin folders, but a subsequent sed call replaced the links with
changed files. The original files have also been changed with another sed
call in the same way. This resulted in the duplication of the changed
files.

The plugins of the roles are now moved into the global plugin folders and
only changed there. The now empty plugin folders in the roles are
removed.