Add optical generator data and update pre-generators

[amandalund]

This adds the pre-step data and buffers needed for generating and storing the optical distribution data and updates the pre-generators in preparation for #1173.

[sethrj]

Thanks @amandalund ! Feel free to accept or reject the two suggestions and merge when you decide.

[sethrj]

Since all these data are scalars, I think you might be able to define an OpticalGenParamsScalars and then add

template<Ownership, MemSpace>
using OpticalGenParamsData = OpticalGenParamsScalars;

Then you won't have to write the operator=? Or maybe that's not worth it...

[amandalund]

I like that, but get some errors when using it in the StreamStore so maybe I'll hold off, unless you see what I'm missing?

/home/alund/celeritas_project/celeritas/src/corecel/data/StreamStore.hh: In instantiation of ‘S<celeritas::Ownership::reference, M>& celeritas::StreamStore<P, S>::state(celeritas::StreamId, celeritas::size_type) [with celeritas::MemSpace M = celeritas::MemSpace::host; P = celeritas::OpticalGenParamsData; S = celeritas::OpticalGenStateData; celeritas::StreamId = celeritas::OpaqueId<celeritas::Stream_>; celeritas::size_type = unsigned int]’:
/home/alund/celeritas_project/celeritas/src/celeritas/optical/detail/PreGenAction.cc:126:69:   required from here
/home/alund/celeritas_project/celeritas/src/corecel/data/StreamStore.hh:206:21: error: no match for ‘operator=’ (operand types are ‘celeritas::CollectionStateStore<celeritas::OpticalGenStateData, celeritas::MemSpace::host>’ and ‘<brace-enclosed initializer list>’)
  206 |         state_store = {this->params<MemSpace::host>(), stream_id, size};
      |         ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/alund/celeritas_project/celeritas/src/celeritas/global/CoreState.hh:14,
                 from /home/alund/celeritas_project/celeritas/src/celeritas/global/ActionLauncher.hh:17,
                 from /home/alund/celeritas_project/celeritas/src/celeritas/optical/detail/PreGenAction.cc:13:
/home/alund/celeritas_project/celeritas/src/corecel/data/CollectionStateStore.hh:77:34: note: candidate: ‘template<celeritas::Ownership W2, celeritas::MemSpace M2> celeritas::CollectionStateStore<S, M>& celeritas::CollectionStateStore<S, M>::operator=(const S<W2, M2>&) [with celeritas::Ownership W2 = W2; celeritas::MemSpace M2 = M2; S = celeritas::OpticalGenStateData; celeritas::MemSpace M = celeritas::MemSpace::host]’
   77 |     inline CollectionStateStore& operator=(S<W2, M2> const& other);
      |                                  ^~~~~~~~
/home/alund/celeritas_project/celeritas/src/corecel/data/CollectionStateStore.hh:77:34: note:   template argument deduction/substitution failed:
In file included from /home/alund/celeritas_project/celeritas/src/celeritas/optical/detail/OpticalGenStorage.hh:12,
                 from /home/alund/celeritas_project/celeritas/src/celeritas/optical/detail/PreGenAction.cc:22:
/home/alund/celeritas_project/celeritas/src/corecel/data/StreamStore.hh:206:21: note:   couldn’t deduce template parameter ‘W2’
  206 |         state_store = {this->params<MemSpace::host>(), stream_id, size};
...