Grey out GPU settings rather than removing when not supported

When `gpu.renderstages` or `gpu.counters` producers are not available, it would be more intuitive if the selections boxes under _Configure_ for GPU →Renderstage slices and GPU → Counters were greyed-out rather than removed entirely.

It would make sense that a tooltip was shown when hovering over them that the relevant `gpu.*` data source producer was not available on the device.

This provides more context that having the top level _GPU does not support profiling_