vulkan/overlay: record stats in command buffers and accumulate on exec/submit

vulkan/overlay: record stats in command buffers and accumulate on exec/submit

This significantly reworks how numbers displayed are computed. We
accumulate operations written into command buffers and add those to
the device when submitted to a queue. These collected values are then
used to compute per frame overlay data.

We also accumulate the data over the sampling fps period to produce
numbers for that period of time.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>