add flexibility to AerosolDistribution specification

[claresinger]

Right now AerosolDistribution expects each AerosolMode to have the same number of components. It would be nice to make this more general. E.g. so you can have AM1 with just sulfate and AM2 with a mixture of sulfate and insoluble.

See example of what must be done currently to avoid this "feature" here:

CloudMicrophysics.jl/docs/src/ARGplots.jl

Lines 50 to 82 in 0a1b181

	if X in (1,4)
	mass_mixing_ratios_1 = (1.0,)
	n_components_1 = 1
	paper_mode_1_B = AM.Mode_B(
	r_dry_1,
	stdev_1,
	N_1,
	mass_mixing_ratios_1,
	(ϵ_sulfate,),
	(ϕ_sulfate,),
	(M_sulfate,),
	(ν_sulfate,),
	(ρ_sulfate,),
	n_components_1,
	)
	end
	if X in (2,3,5)
	mass_mixing_ratios_1 = (1.0,0.0)
	n_components_1 = 2
	paper_mode_1_B = AM.Mode_B(
	r_dry_1,
	stdev_1,
	N_1,
	mass_mixing_ratios_1,
	(ϵ_sulfate, ϵ_insol),
	(ϕ_sulfate, ϕ_insol),
	(M_sulfate, M_insol),
	(ν_sulfate, ν_insol),
	(ρ_sulfate, ρ_insol),
	n_components_1,
	)
	end