Allow flags to be applied to some field/subtype but not its children

[MateuszKubuszok]

Basically, implement regional flag from Ducktape.

It would be similar to implementation for current scoped flags (or local flags from Ducktape) which are implemented like

chimney/chimney/src/main/scala-2/io/scalaland/chimney/dsl/TransformerDefinition.scala

Lines 394 to 397 in a55f1df

	def withSourceFlag[T](
	selectorFrom: From => T
	): TransformerSourceFlagsDsl.OfTransformerDefinition[From, To, Overrides, Flags, ? <: Path] =
	macro TransformerDefinitionMacros.withSourceFlagImpl[From, To, Overrides, Flags]

chimney/chimney/src/main/scala/io/scalaland/chimney/internal/runtime/TransformerFlags.scala

Lines 17 to 20 in a55f1df

	final class Source[SourcePath <: Path, SourceFlags <: TransformerFlags, Flags <: TransformerFlags]
	extends TransformerFlags
	final class Target[TargetPath <: Path, TargetFlags <: TransformerFlags, Flags <: TransformerFlags]
	extends TransformerFlags

chimney/chimney/src/main/scala/io/scalaland/chimney/internal/compiletime/derivation/transformer/Configurations.scala

Lines 134 to 141 in a55f1df

	def prepareForRecursiveCall(fromPath: Path, toPath: Path)(implicit
	ctx: TransformationContext[?, ?]
	): TransformerFlags = {
	val (immediate, nested) = scopedUpdates.view
	.flatMap { case (path, update) => path.drop(fromPath, toPath).map(_ -> update) }
	.partition(_._1.path == Path.Root)
	immediate.map(_._2).foldLeft(this)((f, u) => u(f)).copy(scopedUpdates = nested.toList)
	}

(separate macro, returning a separate type, handled in Configuration).