Docs: Update Google Cloud products and pricing (#488)
Docs: Update Google Cloud products and pricing (#488)

- Updates the standard compute setup from n1-highmem-8 to n2d-highmem-8 (52 --> 64 GB memory, Intel --> AMD)
 - Updates the budget compute setup from n1-highmem-4 to n2d-highmem-4 (26 --> 32 GB memory, Intel --> AMD)
 - Updates both the standard P4 and budget K80 GPU to the cheaper and faster T4 GPU.
 - Updates storage pricing
 - Add an option for fast SSD storage
fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3,fastai/course-v3