ISMIP7 streams

[trhille]

This issue serves as a to-do list for changes to streams.landice for ISMIP7:

• Change basicmesh to minmesh for output streams. Done in Add hydrofracture mask input to ismip7_run/ismip7_ais test case #989
• Remove uReconstructX/Y and any other unnecessary large fields.
• Add damageCalvingThreshold input stream for AIS
• Add calvingStrainRateScaling input stream for GrIS.
• ISMIP7 melt streams for AIS
• ISMIP6 sub-shelf melt streams for GIS.