backend/native: Add udev rule to ignore vkms devices

Virtual Kernel Mode Setting (vkms) is a virtual /dev/dri/card* device
not backed by any actual hardware. It's intended for testing purposes,
e.g. to run tests suites with a reproducable setup, or in continuous
integration pipelines.

Currently mutter don't have any tests that can run on top of vkms, but
will eventually get that. To prepare for the ability to do that, and
having said kernel module loaded without causing wierd issues with any
active session, add an udev rule that tells mutter to ignore any vkms
device.

Otherwise, when vkms is loaded, mutter would detect it, assume it's a
regular monitor, configure it as such, thus add a region of the stage
that ends up nowhere, which isn't very helpful. It might also conflict
with running actual tests that need to interact with vkms if the active
session has taken control of it.
13 jobs for !1740 with wip/ignore-vkms in 22 minutes and 57 seconds
latest detached
Status Job ID Name Coverage
  Review
passed #1172382
check-commit-log

00:00:21

passed #1172383
check-merge-request

00:00:10

 
  Prepare
passed #1172385
aarch64
build-fedora-container@aarch64

00:00:23

passed #1172384
build-fedora-container@x86_64

00:00:19

 
  Build
passed #1172387
aarch64
build-mutter@aarch64

00:06:35

passed #1172386
build-mutter@x86_64

00:05:46

passed #1172389
build-without-native-backend-and-wayland@x86_64

00:01:04

passed #1172388
build-without-opengl-and-glx@x86_64

00:05:25

 
  Test
passed #1172392
can-build-gnome-shell@x86_64

00:02:03

passed #1172391
aarch64
test-mutter@aarch64

00:07:25

passed #1172390
test-mutter@x86_64

00:04:15

 
  Coverage
passed #1172394
aarch64
test-mutter-coverage@aarch64

00:08:07

45.0%
passed #1172393
test-mutter-coverage@x86_64

00:05:32

45.0%