ci: Fix FIH Docker image release usage

The scripts for fih tests install and run where running different
versions of the docker images, since the install specified a version and
not version was specified for run, defaulting to `latest`.

This commits adds a new file for specifying the docker image to be used.

Signed-off-by: Fabio Utzig <utzig@apache.org>
(cherry picked from commit 4619da56)