[Feature Request] - Convert Strings to enum

[alirezat66]

Is your feature request related to a problem? Please describe.
When I want to use vania, in some parts like validation I have to use Strings like:
'required|max_length:20|min_length:2'
or
'required|email'
or
'file:jpg,jpeg,png'

and I have to go to document to check them.
Describe the solution you'd like
It is better to create enums and also use builder design pattern to make it more readable.