Show stats for multiple GPUs simultaneously

[Konstantin Wilms]

Ability to see and up/down arrow select individual GPUs is fantastic - but it would be even more useful to be able to see all GPU metrics at once.

This is useful for things like loading LLMs across multiple GPUs and monitoring optimal distribution/execution of models across multiple GPUs in one system.

[Benjamin Vaisvil]

Sure, that shouldn't be too difficult.