[RFC] PHPStorm plugin

[murtukov]

Q	A
Bug report?	no
Feature request?	yes
BC Break report?	no
RFC?	yes
Version/Branch	any

Create a PHPStorm plugin to help navigate through GraphQL types, similar to the JS GraphQL plugin. It should recognize any formats, including pure webonyx php types.

Also, as advanced feature, it could show a popup diagram with all GraphQL types and their connections. I will assign it to myself for now and try to work on it, when I have time.

@Vincz @mcg-web provide any feature request here if you have some.