Don't promote daily images and set expectations for booting in VirtualBox

We link to the hardware reference page from the home page, as a result this
page is likely to be one which is visited by people generally unfamilar with
Apertis.

We should not promote the use of daily images to those likely to be looking to
evaluate Apertis - they should be using the stable images.

Booting non-SDK images in VirtualBox is not a supported option, so whilst it
works for many images, this is not guaranteed (and the minimal OSTree images
are known not to boot in VirtualBox). Set expectations with regards to running
in this configuration.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>

content/guides/virtualbox.md

@@ -411,7 +411,14 @@ containing the virtual machine intact.
 
 We recommend running minimal, target and development images on
 [real hardware]( {{< ref "/reference_hardware/_index.md" >}} ), but VirtualBox
-can run our `amd64` images.
+may be able to run some of our `amd64` images.
+
+{{% notice warning %}}
+Running non-SDK images on VirtualBox or other virtual machines is not
+officially supported, though many of the images do. If the image type you are
+interested in evaluating does not boot in VirtualBox, there is a good chance
+that it may boot in [QEMU](https://www.qemu.org/).
+{{% /notice %}}
 
 - Download the `.img.gz` and `.img.bmap` files for the image you need from the
   [image repository]( {{< ref "/images.md" >}} )

content/reference_hardware/_index.md

@@ -19,10 +19,8 @@ span the Intel 64-bit, ARM 64-bit and ARM 32-bit architectures:
 - [Optional extra reference hardware]( {{< ref "/reference_hardware/extras.md" >}} )
 
 Various prebuilt [images]( {{< ref "images.md" >}} ) are available for testing.
-Apertis development is fasted paced, so we recommend that you use the daily
-build images whenever possible.
 
 If you currently don't have access to any of the supported hardware, the
-`amd64` images can be run on a
-[virtual machine]( {{< ref "/guides/virtualbox.md" >}} ).
+`amd64` images might run on a
+[virtual machine]( {{< ref "virtualbox.md#non-sdk-images" >}} ).