GraphQL: consider adding a helper method for defining negated arguments

We settled on the format of passing negated arguments (!41350 (merged)). There are various options to defined the list of arguments which can be negated. One of elegant options which was suggested by @alexkalderimis in !41350 (comment 416036126) is having a helper resolver method which would limit the size of boilerplate for negated args definition.

Because at the moment of documenting negated args (!41350 (merged)) it wasn't used in the code, we didn't add it into documentation, but it seems to be an elegant solution to consider when anyone will be adding negated args for a resolver.