Update to v1.0.0-alpha.7 and mpas_tools 1.6.0

[xylar]

The new mpas_tools brings in major performance improvements to mask generation on MPAS meshes.

Checklist

• Testing comment in the PR documents testing used to verify the changes

[xylar]

Testing

I ran successfully ran:

e3sm/init/icos30km/topo/cull

I'm still seeing the performance gains (20x speed-up in masking) reported in MPAS-Dev/MPAS-Tools#719 (comment), which is the point of the PR.

I also successfully ran the omega_pr suite on Chrysalis with Intel. I didn't give it a baseline because I didn't expect any Omega tests to be affected. They don't use this masking to my knowledge.

[xylar]

Since this is mostly for the unified mesh workflow and I don't expect it to affect others, I'm going to merge once CI passes.