Make DataValidationType a data-bound enum

[2ndDerivative]

It would probably be very "rusty" to change the data validation type from a blank enum with possibly unused fields to an enum with fields like so

pub enum DataValidationType {
    None,
    Integer(i64),
    List(Vec<String>)
}

and so on. If that's too much work I will look into it, but it would probably be good to leverage the type system to ensure data field completeness at the point where Rust usually expects it.

[2ndDerivative]

I was looking into it and was wondering what the difference between "None" and "Any" in the data validation enum is @informationsea

Edit: I am sorry for spamming closed/reponen, didn't notice the button had went "close with comment"

[2ndDerivative]

45 I have made a proposal to solve this issue

[informationsea]

Thank you for pull request. I merged.