set options in pagination helpers for tests instead of long parameter list

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
separated request-building in tests due to complexity with building queries

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
when selecting a mirror, correctly query /packages with the selected mirror id

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
bugfix: pagination requests must correctly propagate query options when iterating

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
feature: query packages with a selected repository

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>