[Request] Typescript types

[AdrienLemaire]

Add types for all neo4j-graphql.js exports to https://github.com/DefinitelyTyped/DefinitelyTyped

Or rewrite the project using typescript.

Same request as neo4j-graphql/neo4j-graphql-js#275, these are the only 2 dependencies missing types in my project, and make it difficult to resolve issues like #24