Add normalize method

[adam-mccormick]

This PR adds a normalize method to the Validator class. This method can take a schema, type, or string and resolve all shorthands and turn it into a 'normalized' form of a fastest-validator schema. This is useful for being able to inspect a schema and not have to worry about dealing with short hands, aliases, etc.

For example:

validator.normalize({ a: "string[]|optional" })

Will result in:

{
  a: {
    type: "array",
    optional: true,
    items: {
      type: "string"
    }
  }
}

Not a typescript guy so the ts definition of this method may not be super correct.

There's some duplication with the getRuleFromSchema method but I didn't want to make any changes there. Happy to revisit if required.

[icebob]

Thanks for the PR. I don't like that the same logic is implemented in both places. Later we have an inconsistency state if somebody makes changes in getRuleFromSchem but forget to update normalize as well.

Please move the duplicated parts into one method and call it from both.

[adam-mccormick]

@icebob I've moved the duplication to a new method. Let me know if there are any other changes you'd like to see.

[icebob]

Why is it removed?

[adam-mccormick]

The getRuleFromSchema method modifies the passed schema and the refactor moves some of that logic to a method used by both it and normalize. The schema passed to normalize will be modified as well which I think makes it more in line with the rest of the API.

[icebob]

Thanks, great PR!