make Pack composition more modular by using Pack dependencies

[ksatirli]

Currently, most Packs duplicate almost identical code.

With Pack Dependencies, as released in nomad-pack 0.1.0, a part of the duplicated code can be moved to a singular "utility" Pack.

The code in this will set the stage for #3, #14, #21

[ksatirli]

Preliminary work for this is done in #28, all older Packs should be updated to use this new structure.