Handle multiple exceptions

[Maximilien-R]

In some cases, it may be relevant to not only raise the first exception encountered and allow multiple exceptions to be handled at one time.

In the case of directives and in particular on_argument_execution the fact of handling several errors could be interesting:

type Query {
    search(
        query: String! @maxLength(limit: 50)
        page: Int! = 1 @maxValue(limit: 10)
    )
}

Currently, if the directives for these two arguments raise an exception, only the first raised exception will be returned as an error (bypassing the second). But it could be useful to return both errors at the same time.