Revisit AlgorithmName constructors

[charleskawczynski]

#152 added constructors for subtypes of AbstractAlgorithmName:

# (::Type{Name})(newtons_method::NewtonsMethod) where {Name <: IMEXAlgorithmName} = IMEXAlgorithm(Name(), newtons_method)

#= Convenience constructor =#
(name::IMEXAlgorithmName)(newtons_method::NewtonsMethod) = IMEXAlgorithm(name, newtons_method)

The former method would enforce compatibility with OrdinaryDiffEq, however, it's incompatible with certain subtypes of AbstractAlgorithmName, for example:

Base.@kwdef struct SSP333{FT <: AbstractFloat} <: IMEXSSPRKAlgorithmName
    β::FT = 1 / 2 + √3 / 6
end

We may need to rethink either how this parameter comes in, or if the OrdinaryDiffEq pattern is worth maintaining.

[dennisYatunin]

Potential solution:

(::Type{Name})(newtons_method::NewtonsMethod, args...) where {Name <: IMEXAlgorithmName} = IMEXAlgorithm(Name(args...), newtons_method)

The definition's somewhat clunky, but it could be helpful for people familiar with the OrdinaryDiffEq syntax. The functor syntax looks kind of confusing (e.g., SSP333()(newtons_method)), so I don't think people will use it much.