Changes to site documentation

Mostly just formatting fixes with a few grammatical changes.

Two real notable changes:
  - Removed references to SkGLCanvas from Tips & FAQ and replaced with
    references to `SkDevice` and `SkSurface`.
  - Deleted deprecated "Quick Start Guides" folder

Docs-Preview: https://skia.org/?cl=92361
Bug: skia:
Change-Id: Ief790b1c2bae8fe0e39aa8d66c79f80560d18c9e
Reviewed-on: https://skia-review.googlesource.com/92361
Reviewed-by: Heather Miller <hcm@google.com>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
Commit-Queue: Joe Gregorio <jcgregorio@google.com>
diff --git a/AUTHORS b/AUTHORS
index 6def302..6ebbda8 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -15,6 +15,7 @@
 Anthony Catel <paraboul@gmail.com>
 ARM <*@arm.com>
 Ehsan Akhgari <ehsan.akhgari@gmail.com>
+Facebook, Inc. <*fb.com>
 George Wright <george@mozilla.com>
 GiWan Go <gogil@stealien.com>
 Google Inc. <*@google.com>