feat(node): unified node constructor

[Wondertan]

Context

In #86 we moved Open/Init/IsInit functions over the unified pattern where they receive Node Type as param. Now, it makes total sense to introduce a New Node constructor to would instantiate a Node for a given type. For now, old constructors(NewFull/NewLight) are preserved, same as with DefaultLight(Full)Config but we can make them private and/or remove them if we find a reason for that in future

[liamsi]

lgmt

[Wondertan]

@Bidon15, @liamsi
Well, I can decide myself whether we should make Default(Type)Config() and New(Type) private. I have arguments in my hand for public and private semantics, and I like them both. So let's vote with thumbs up on the comment for making them private or thumbs down for keeping them public.

[renaynay]

Pls make NewFull and NewLight private, otherwise lgtm

[Wondertan]

• Removed New(Type) and Default(Type)Config entirely
• Slightly enhanced lifecycling

[Bidon15]