Kokkos-aware Clad

[kliegeois]

This PR provides the implementation of a first set of features for the automatic generation of gradients of Kokkos-based code.

The content of this PR supports reverse mode of Kokkos parallel_for, deep_copy, and view accesses.

@vgvassilev @brian-kelley

[vgvassilev]

@kliegeois, @brian-kelley, is there a point to try to rebase this PR or @gojakuch should continue picking random things from it as it is now?

[kliegeois]

@vgvassilev I am not sure what is best. If we rebase, would @gojakuch still create different PRs that refactor this PR? If yes, the rebase is not necessarily useful although it will be easier to highlight the remaining pieces.