Move Value.ArrayType to Type.Array

[slaymaker1907]

I'm not sure why this is in the Value namespace.

[Sheyne]

Eventually ArrayX, MapX, SetX, etc (for X = Value | Type) will be moved to a separate typed Javascript package that'll be separate from the conceptually pure sinap-types. That's why they're all named differently. The issue is that they can't (couldn't? maybe they can now) be separated yet.

[slaymaker1907]

That makes sense. We should probably just handle generics in sinap-types and then leave the more specific stuff to the other package.