Revisit all API list calls to deal with the pagination

[lubosmj]

A generic fixture will be added to pulpcore. Concrete implementation will be done on the plugin side.

In this task, we will revisit all calls, like: rpm_package_api.list(repository_version=repository.latest_version_href).results. De-pagination should be done in the background in case of multiple items are being returned from the API.

    def get_upstream_distributions(self, labels=None):
        if labels:
            params = {"pulp_label_select": labels}
        else:
            params = {}
        offset = 0
        list_size = 100
        while True:
            distributions = self.distribution_ctx_cls(self.pulp_ctx).list(list_size, offset, params)
            for distro in distributions:
                yield distro
            if len(distributions) < list_size:
                break
            offset += list_size

[lubosmj]

I am unassigning myself from the task because it is not prioritized.