scripts/test-remote-image: Add script for running runtime tests on remotely built...

scripts/test-remote-image: Add script for running runtime tests on remotely built images

YB: #6254

Adding a new script that will fetch image files from a remote images repository.
These images will then be used for local runtime testing.

Use the '-h' option for more details on usage.

Signed-off-by: Corneliu Stoicescu <corneliux.stoicescu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>