Make documentation available for Python API

[mgeplf]

• CircuitConfig, NodeSets, and SimulationConfig didn't have a top level docstring and thus sphinx automodule wasn't displaying them

braynscircuitstudio/fake-backend/src/api_sonata_list_populations.py?r=01bd1007809656a55239de478601cb1ac4adfc16 libsonata._libsonata.Report.Type

BlueBrain/BlueCelluLab/bluecellulab/circuit/config/sections.py?r=dbe824ac754fe878a37acf99b57d6ed968045106 from libsonata._libsonata import Conditions as LibSonataConditions

• SNAP tests have been updated to handle the different versions

[mgeplf]

I'm going to wait to merge this until @WeinaJi has a chance to look.