Add legacy Nvidia, AMD and Intel GPU support

With OpenCore 0.6.2, more legacy OSes will be supported including both EFI32 and EFI64 firmwares. So while the userbase may be small, adding support for older hardware is quite beneficial as the majority of legacy threads rely on modified distros that may rely on Chameleon and Clover attributes. Currently we have a 0.6.2 PR coming end of this month with support for Yonah through Nehalem however we're relying on users doing research themselves to resolve their GPU issues.

For this, I'd like to add guides for the following:

- [x] NVCAP Calculations for NVIDIA GPUs
- [x] 6 series through Fermi
- [x] ACPI patching around Intel GMA line
- [x] GMA 900 and GMA 950 for both laptop and desktops
- [x] GMA X3100 for laptops
- [ ] Numerous DeviceProperties required for AMD
- [ ] X1000 through HD 6000 series

Ref:
- [NVCAP](https://github.com/acidanthera/WhateverGreen/blob/master/Manual/NVCAP.bt)
- [AMD Sample](https://github.com/acidanthera/WhateverGreen/blob/master/Manual/Sample.dsl)
- [GMA950](https://www.applelife.ru/threads/intel-gma950-32bit-only.22726/), [GMA X3100](https://www.applelife.ru/threads/intel-gma950-32bit-only.22726/)