Generate test volume data

## Use Case
As a developer implementing volume time series rendering, I want to test with data from VCell so that I can make sure to support common modeling outputs.

## Acceptance Criteria
Dataset from VCell in ZARR format

## Details
[initial converter](https://github.com/simularium/simularium-viewer/blob/volume-agents/scripts/vcell_zarr_converter/convert_vcell_test_data.py)
