Pure SoA Particles: ParticleTileData Size Optimization

[ax3l]

Follow-up marked in #3290 by @AlexanderSinn:

The ParticleTileData struct that is used to access SoA data can be very large, over 300 bytes in some cases. I recommend changing the array-of-pointers to a full 2D array. This way ParticleTileData could be as small as 24 bytes (real pointer, int pointer, stride).

@atmyers what do you think?

[ax3l]

@AlexanderSinn do you like to post a draft PR for this change?

[asalmgren]

Closing this issue due to lack of activity. Please re-open it if you feel there is is still an issue!