COMPMID-3249: Remove non-public data submodule and mirror Github behaviour

This patch removes the `data` submodule and replaces it with the Github
version of the data folder.

Change-Id: I541880d7a823eb6eecdde8ee4fab28596efee02b
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/3094
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/data/images/1280x720.ppm b/data/images/1280x720.ppm
new file mode 100644
index 0000000..9559775
--- /dev/null
+++ b/data/images/1280x720.ppm
Binary files differ