Extend ctx.rule with raw rule params

[alko999]

In v3 we can show a names of fields in cross-fields validation messages, but it not supported in v4 without rewriting of validations and rules.
As example in v3 we can define "customConfirmed:@password" and get "password" (not "password" value) during message generation.
In v4 in generateMessage function we only get ctx.rule.params with value of "password" field, but we can't get field's name....

Describe the solution you'd like
Please, add ctx.rule.rawParams as a raw validation params ( ["password"]), so we can handle them in generateMessage manually and form a correct message.
Or, like in v3 object, like { password: "password" }