bitbake.conf: Enable opengl ptest multiarch wayland vulkan in DISTRO_FEATURES by...

bitbake.conf: Enable opengl ptest multiarch wayland vulkan in DISTRO_FEATURES by default

This change enables the modern graphics stack defaults of opengl, wayland and
vulkan, it enables mutliarch which allows gcc, binutils and gdb to target
multiple file formats and it also enables ptests by default

This means that:

* nodistro builds will match the Yocto Project sstate CDN objects
* we have modern graphics defaults
* users will see ptest issues more clearly and be more likely to test
  before sending patches

These DISTRO_FEATURES have been tested and used as defaults in poky for a
long time, this brings them into sync.

Backfill is used so those with their own distro can set the
DISTRO_FEATURES_BACKFILL_CONSIDERED variable to stop the backfill happening
for speccific values.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>