[New Feature] - Addition of volume data to the repository

[alexvalentine94]

Proposal

Add the volumes of each of the cells in an input model to the repository.

Motivation

With MCNP this can be included on the SD card or otherwise set to one and used as a divisor in post-processing. In other codes, this has to be done in post-processing meaning that the list of volumes of the cells need to be stored somewhere.

Secondly, as this is a repository for benchmark inputs, its also makes sense to have some minimal validation of the inputs for the different codes. Comparing the volumes of the cells to the MCNP model is the most common approach. The computed volumes by stochastic methods could be stored alongside each benchmark.

Implementation

This could be included as metadata. Likely we don't want to make the existing metadata.json too busy but could consider volumes.json or .h5 containing the data for each code.

Effort is of course needed to perform the stochastic volume calculation for existing MCNP inputs but this should be performed in parallel with the development of inputs for alternative transport codes (as a validation step of the translation).