Resolve Pysmo sampling causing a requirement on idaes-pse

[lbianchi-lbl]

parameter-sweep/src/parameter_sweep/parameter_sweep.py

Line 21 in b3023b5

from idaes.core.surrogate.pysmo import sampling

Possible solutions (in rough order of increasing effort needed):

1. Make the availability of the Pysmo sampling schemes contingent on whether Pysmo is importable (i.e. making idaes-pse an optional, rather than required, dependency)
2. Copy the code from Pysmo to this repository
3. Look into whether Pysmo can be made distributable as a standalone package independently from idaes-pse