How to specifiy response properties in qcschema jobs

[jthorton]

Describe the bug
I wish to calculate the dipole polarizabilities using psi4 but the way to specify this is not clear. In an energy calculation, I can supply a list of scf properties in the keywords like so

from qcelemental.models.common_models import Model
from qcelemental.models import AtomicInput, Molecule
import qcengine

mol = Molecule.from_data("""
     O  0.0  0.000  -0.129
     H  0.0 -1.494  1.027
     H  0.0  1.494  1.027
     """)
# create the psi4 job
spec = Model(method="HF", basis="3-21g")
task = AtomicInput(
    molecule=mol,
    driver="energy",
    keywords={"scf_properties": ["MBIS_CHARGES"]},
    model=spec
)
result = qcengine.compute(input_data=task, raise_error=True, task_config={"ncores":1}, program="psi4")
print(result.dict())

but the properties driver requires a more complicated definition of keywords

from qcelemental.models.common_models import Model
from qcelemental.models import AtomicInput, Molecule
import qcengine

mol = Molecule.from_data("""
     O  0.0  0.000  -0.129
     H  0.0 -1.494  1.027
     H  0.0  1.494  1.027
     """)
# create the psi4 job
spec = Model(method="HF", basis="3-21g")
task = AtomicInput(
    molecule=mol,
    driver="properties",
    keywords={"function_kwargs": {"properties": ["dipole_polarizabilities"]}},
    model=spec
)
result = qcengine.compute(input_data=task, raise_error=True, task_config={"ncores":1}, program="psi4")
print(result.dict())

would it be possible to make this simpler and remove the need to have function_kwargs or even allow the inputs to be the same as all scf properties seem to also be valid inputs for the property calculation?