Ditch some older NSO versions

Removing 4.4.7 and with it, the whole 4.4 train. It's just too old, for example not supporting "request package reload force", which we want for #51 (closed). The goal for NSO in Docker is not to support all currently supported versions of NSO, but rather a set of versions that are reasonably easy to support, primarily targeting NSO 5. NSO 4.4 is simply too old and would involve making exceptions that hurt the overall user experience of NSO in Docker.

Also removing 4.5.9 which just seems out of place.