Refactor existing builders

[Pyrofab]

So I did a bit of a mess of generics and inner classes in my previous builder pass. I figured most of that was unneeded, so I toned it down a bit.

• ConfigValueBuilder and ConstraintsBuilder are not abstract anymore and replace the Scalar-specific builders
  • More intuitive
  • Fewer useless classes
  • You technically can use scalar builders on aggregates, if you don't care about component constraints, so no need to force the separation
• Aggregate builders are off to separate files
• No more self generics, we are back to overriding the methods in every class
  • Fewer generics = good, right ?
  • Method duplication is not great, but it does improve discoverability
• Fewer factory methods

[zeroeightysix]

Spotless! Thanks.