Adding vector atomic_add and update CIC interpolation to work with vector valued quantities.

[JoMee]

This PR creates a wrapper around the Kokkos atomic_add function and adds another atomic_add function for ippl vectors.

A new type is added for the quantity to be scattered in CIC interpolation to allow for vector-valued quantities.

The wrapper around the atomic_add function is placed in Utility/ParallelDispatch as discussed with Sri (I would double check if there is not a better place for that?).

Unit tests are added.

Tests are added for isolated usage.