libweston: Print fps for all surfaces

This is introduced to get the fps for all surfaces on the fly.

Weston's timeline feature is useful for analyzing the rendering
performance, but we cannot see the actual result until profiling
is finished.

This introduces a simple configuration in weston.ini:
[core]
surface-fps=true

The default value is false, so no behavioral change is introduced.
2 jobs for enable-surface-fps in 3 minutes and 30 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #25955
build-native

00:03:30

failed #25954
build-native

00:00:11