Move plonkup code to plonkup repository

[moCello]

Describe what you want implemented
We used to have the plonkup protocol in the plonk repository. But with issue #684 in plonk, we reverted the plonk repository to only contain plonk and moved the plonkup code here. This issue fixes the last hickkups that stemmed from that move

Describe "Why" this is needed
To be able to use both plonk and plonkup

Describe alternatives you've considered
The alternative is to separate plonk and plonkup in the same crate and depending on our use cases we might also still do that. But for now we opted for the easier option to have two separate crates.

Additional context
N/A