[Feature request] Add introspection options for fetching GraphQL schemas.

[MayCXC]

The graphql spec has added several optional fields and arguments to introspection queries, which graphql-js supports with an options interface to include deprecated input fields, __Schema.description, __Directive.isRepeatable, __Type.specifiedByUrl, etc.. It is very useful for developing graphql servers to have these fields present in the schema documentation, especially deprecated input fields.

I have a fork that adds a switch for each of these options beneath the "Remote GraphQL schema" section in the graphql query settings pane, as well as addressing what I think is a bug where the schema documentation doesn't get updated when "Refresh schema" is clicked, here: #5329

Adding options for each of these rather than just using the most general possible query is useful because many existing graphql servers cannot resolve all of the spec's fields; I have a few graphql-java projects that can't validate queries which use __Directive.args with arguments, so disabling it is nice.