[ENHANCEMENT] Define default parameters one at a time based on parameter names

[mtfishman]

Right now, we define default parameters like this:

default_type_parameters(::Type{<:Array}) = (Float64, 1)

i.e. as a list, which is expected to be the length of the number of parameters and also follow the positional ordering of the parameters of the type. That is a bit clunky, relies on too many low level details of the type, etc.

A better approach would be:

default_type_parameter(::Type{<:Array}, ::typeof(eltype)) = Float64
default_type_parameter(::Type{<:Array}, ::typeof(ndims)) = 1

which was actually one of the original designs but we found it was difficult to make type stable. But it would be good to revisit that design and get it working.