Improve validation checks for the topic directive

[DawidNiezgodka]

Below, some examples which show invalid behaviour or missing checks.

1. Validation of keyArguments

type Product {
    id: ID!         
    name: String!   
}

type Query {        
    getProduct(id: ID): Product @topic(name: "product-topic")    
}   

The query is missing the keyArgment but since the mutation rule passes no error will be thrown.
Another example:

type Query {
    getProduct(productId: ID): ProductInfo
}

type ProductInfo {
    product: Product @topic(name: "product-topic")
    url: String @topic(name: "url-topic", keyArgument: "productId")
}

2. Validation of the rule with one input argument of a mutation type.

type Mutation {
    setClick(clickCount: Long): Long @topic(name: "click-topic")
}  

It should contain 2 inputs.