Variables as part of a GraphQL operation

[esteiner]

To support queries like:

query DocumentsList($limit: Int!, $filter: String, $andCondition1: DocumentView_bool_exp!) {
    documents: DocumentView(
        where: { _and: [
            { _or: [
                { mandate: { _ilike: $filter }},
                { category: { _ilike: $filter }},
                { label: { _ilike: $filter }},
                { documentId: { _ilike: $filter }},
                { createdBy: { _ilike: $filter }},
            ]},
            $andCondition1
        ]},
        limit: $limit
    ) {
        documentId
        version
        mandate
        filename
    }
}

andCondition1 = { createdAt: { _gte: this._getFromDate() } }