* Bury Best Practices, for the time being.
* Bury Schema, but leave it on disk.
* Introduce new Querying section.
* Move "Why Apollo Server?" into "Index".
* ...to be refined.
* Remove no-longer-helpful "Getting Started" from "Index".
cc @stubailo @evans @peggyrayzis @JakeDawkins @unicodeveloper @jbaxleyiii
