Add multiple `Var` operations in example `CRTest`

[ronanM]

Add operations with multiple Var in hedgehog.examples.state.CRTest, to explain how to mix operations with single Var and operations with multiple Var in the model.

For example:

def createList(vs: List[String]): List[CRId]

def readList(ids: List[CRId]): List[Option[String]]

Maybe related with:

• https://github.com/hedgehogqa/haskell-hedgehog/issues/113

I don't know how to write in Scala this trick:

• https://github.com/hedgehogqa/haskell-hedgehog/issues/459#issuecomment-1152383992