refacts vsplit from sakila to generic

src/main/kotlin/unibz.cs.semint.kprime/domain/Xrule.kt

src/main/kotlin/unibz.cs.semint.kprime/domain/ddl/Schema.kt

...n/unibz.cs.semint.kprime/usecase/XPathTransformUseCase.kt

.../kotlin/unibz.cs.semint.kprime/scenario/SakilaRefactTI.kt

...z.cs.semint.kprime/scenario/SakilaTransfomerScenarioTI.kt

src/test/resources/transformer/sakilaVTransfomer.xml

...nsformer/vertical/decompose/vertical_changeset_1.template

...transformer/vertical/decompose/vertical_decompose_1.paths

...nsformer/vertical/decompose/vertical_decompose_1.template

src/test/resources/transformer/verticalTransfomer.xml