Unify argument orders

[xukai92]

Currently the order of internal functions on the hamiltonian, phasepoint, kernel/trajectory are not all consistent.
We should make all of them having a order of (rng, hamiltonian, kernel, z).

Also see https://github.com/TuringLang/AdvancedHMC.jl/pull/247/files#r579401575