The Graphics section on the OpenCore Install Guide is outdated

## Guide(s) in question
Dortania's OpenCore Install Guide

## Link to page(s) with the issue
https://dortania.github.io/OpenCore-Install-Guide/ktext.html#Graphics

## Clearly explain the issue(s) with the page(s) (if there is a visual issue, a screenshot is required)
Currently, the guide only mentions the existence of WhateverGreen for graphics. While this might have been correct in the past, the [NootedRed](https://github.com/ChefKissInc/NootedRed) and [NootRX](https://github.com/ChefKissInc/NootRX) projects are now a thing and allow for graphic acceleration on AMD Vega iGPUs and RDNA 2 desktop GPUs respectively.

Another issue caused by this is that the install guide mentions that all GPUs benefits from WhateverGreen and that it is required, however, as mentioned by #346, NootedRed and NootRX conflict with it and will cause issues.

If these kernel extensions are added to the guide, there are a couple of things that should be mentioned:
- NootedRed and NootRX cannot be used at the same time (similar to the previously mentioned WhateverGreen issue)
- Both NootedRed and NootRX cannot be used during upgrades or the install process because of a Lilu bug
- Both projects have a couple of other known issues in their bug trackers:
- https://github.com/ChefKissInc/NootRX/issues
- https://github.com/ChefKissInc/NootedRed/issues

## Include possible fixes
The developer(s) of NootedRed and NootRX have their own site with some information about AMD hackintoshes:
- https://chefkissinc.github.io/guide
- https://chefkissinc.github.io/nootedred
- https://chefkissinc.github.io/nootrx

Start at the Graphics section of Dortania’s OpenCore Install Guide, linked in the issue, and review the referenced NootedRed, NootRX, and Lilu information. Done means the guide covers the applicable projects, their incompatibilities and installation or upgrade limitation, with links to their known-issues resources.

Written by the indexing model from the issue text.