Add particle confinement proxies

[f0uriest]

such as Nemov's original $\Gamma_C$ link or the newer $\Gamma_\alpha$ link

[rahulgaur104]

Kaya and I will try to finish the bounce averaging PR this week. Once that is done, we can all the different types of gammas and epsilons.

[dpanici]

jc/gammaC is the branch where the code from our intern Jackson is from his implementation, not completely finished but all of the main equations are coded up there so will be a good start, we would just need to take those and put them into Kaya's framework for the field-line bounce integrals

[rahulgaur104]

I think it would be much easier for me to write my own GammaC code than to understand and rewrite Jackson's code. Once we have a simpler version ready, we can borrow specific parts like vectorization etc. from his branch.

[unalmis]

Maybe just make new issue for new proxies like we did with max j etc since gamma_c is done.