clutter-stage-view: Reimplement CLUTTER_SHOW_FPS

Since a9a9a0d1 it didn't print anything. Now we reimplement it to
show FPS to a higher precision than in 3.36, add update/render times,
and separate stats per view/CRTC.

GNOME/mutter!154
6 jobs for !154 with better-show-fps in 8 minutes and 27 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Review
passed #890868
check-commit-log

00:00:10

 
  Build
passed #890869
build-mutter

00:03:19

passed #890871
build-without-native-backend-and-wayland

00:01:51

passed #890870
build-without-opengl-and-glx

00:04:11

 
  Test
passed #890873
can-build-gnome-shell

00:02:05

passed #890872
test-mutter

00:05:06