main: filter log debug logs by default in new logic

renderer: move blit back to CPU by default

There are some performance issues that lead to tearing when canvas rendering
is used on non-Apple Silicon devices and many blit operations happen in a
short period of time. This is likely due to bandwidth issues. On Apple
Silicon, with unified memory, there is no advantage of GPU blit anyways.
We default back to CPU bliting unless the client specifically requests GPU.

display: GL draw does not need to reschedule on SPICE main queue

display: decouple screenshot utility from main queue

There are some weird deadlock behaviour that happens when we call
the screenshot property from the main thread. It is not documented anywhere
that submitting command buffers to Metal might block on the main thread but
it seems to happen.

main: fix use-after-free in dealloc

display: support enabling/disabling the display

display: disable buggy screenshot code

spice: check to ensure channel is never NULL

usb: expose identifiers to client

display: re-use existing GL texture on device change

If we are setting up a new MTLDevice, we cannot read the FD pipe again
to get the IOSurfaceID, so we have to re-use the existing IOSurfaceRef
from the MTLTexture.