Improve input_state by returning populated data structures

[jcurtis2]

Returning data structures rather than passing them in as arguments. This is useful for when using input_state to read input from a output files where the user has no advanced knowledge of AeroData, GasData, etc. Previously the user would have to provide some amount of minimal information to their constructors (such as a single species to AeroData as done in test_aero_data.py, etc.).

Previously you'd need some minimal information (that would actually be overwritten by input_state):

gas_data = ppmc.GasData(("SO2",))
aero_data = ppmc.AeroData(({"H2O": [1000 * si.kg / si.m**3, 1, 18e-3 * si.kg / si.mol, 0]}))
gas_state = ppmc.GasState(gas_data)
aero_state = ppmc.AeroState(aero_data, n_part, "nummass_source")

[slayoo]

@jcurtis2, do we need to have these empty constructors exposed in Python? IIUC, objects constructed this way are not usable. Would it be possible instead to have these empty constructors only in C++, and expose some read-from-file factory methods returning usable Python objects?

[slayoo]

CI fails on those setups where the freshly released SciPy 1.14.0 is used, which is due to an incompatibility on PyMieScatt side caused by scipy/scipy#20278

Reported upstream: bsumlin/PyMieScatt#25

For the time being, adding a constraint on version of SciPy to the setup.py file (only for CI)