Feature: Add blank line between type definition and members

[nojaf]

Description

Fantomas now adds type members directly underneath the definition.
Suggestion would be to introduce a setting to control if there should be a blank line between definition and members.

type Range =
    { From : float
      To : float }
    member this.Length = this.To - this.From

type MyRecord =
    { SomeField : int }
    interface IMyInterface

type Foo =
    | Bar
    | Meh
    member this.Fluey = ()

would become

type Range =
    { From : float
      To : float }

    member this.Length = this.To - this.From

type MyRecord =
    { SomeField : int }

    interface IMyInterface

type Foo =
    | Bar
    | Meh

    member this.Fluey = ()

Setting

Setting name could be something like NewlineBetweenTypeDefinitionAndMembers.
Other suggestions are welcome.
Default value would be false.

[nojaf]

@nojaf don't forget signature files ;)