* ggml-virtgpu: add backend documentation
Assisted-by-AI: Claude Code
* CODEOWNERS: add /docs/backend/GGML-VirtGPU/ -> kpouget
* README: add the link to docs/backend/GGML-VirtGPU/ggml-virt.md
* docs/ggml-virt: add link to testing + configuration
* Revert "CODEOWNERS: add /docs/backend/GGML-VirtGPU/ -> kpouget"
This reverts commit 8ece8e72e24d305f308505c08ebb75804546374e.
* drop the ggml- prefix
* s/ggerganov/ggml-org
* Relocate VirtGPU.md
* reorganize the text
* turn turn the ascii diagram into a mermaid
* README.md: update the link to the main doc
