Requesting merge of group-related exercises.

[OwnerOfJK]

The exercises that we added explore group theory and the different group axioms.

We focus on group theory to enable developers to get a better intuition for finite fields. This might be pretty low level but for devs who would like to better understand the math behind finite fields, this will be helpful.

The finite field specific exercises will be added next week.

[rutefig]

For the math part, finite fields and modular arithmetic I think it can also be benefitial to have rust exercises but can we align better with what was already done: https://github.com/rutefig/zklings/blob/main/exercises/math/README.md

Instead of doing something from the beginning you can improve what is already done and add the rust exercises but respecting the structure that was done from the beginning pls. We can chat about this if you want

[rutefig]

LGTM 👍🏼