CubeSphereRestart can only read/plot 2D variables

[CoryMartin-NOAA]

Current behavior (describe the bug)

The CubeSphereRestart IO data routine can only currently handle reading 2D variables like t2m, and needs to be able to read 3D variables. EVA plotting can already handle plotting slices.

To Reproduce

Try reading a 3D variable from a FV3 FMS RESTART file

Expected behavior

3D variables can be read by EVA

Additional information (optional)

[CoryMartin-NOAA]

This is being worked on in feature/3d-fv3 starting now

[CoryMartin-NOAA]

Closed through #105