Use Kokkos::View labels

[klappi-s]

Arose from discussion in #434.

Issue: Use Kokkos::View labels

Kokkos provides a label for views which can be set when using standard allocating constructors and which can be retrieved with label()
see: https://kokkos.org/kokkos-core-wiki/API/core/view/view.html#_CPPv4NK4View5labelEv

from Kokkos::View Class Interface

in "Constructors"

template<class IntType>
View(const std::string &name, const IntType&... extents)

View(const std::string &name, const array_layout &layout)

Parameters:

• name: a user provided label, which is used for profiling and debugging purposes. Names are not required to be unique.

in "Other Utility Methods"

const std::string label() const;

Returns:

• the label of the View.

TODOs:

Ideally we wan't to label views for:

• ippl::ParticleAttrib (replace name_m)
• ippl::Field
• other ?