CI: Cover zypper erros with okurz/retry and exponential retries

Related progress issue: https://progress.opensuse.org/issues/162848

tools/test_containers_compose

@@ -20,9 +20,16 @@ wait_until() {
 }
 
 setup_containers() {
-    "$thisdir"/retry sudo docker compose build
+    if command -v retry >/dev/null; then
+        retry="retry -e -s 30 -r 7"
+    else
+        curl -sS https://raw.githubusercontent.com/okurz/retry/main/retry > retry
+        chmod +x retry
+        retry="$PWD/retry -e -s 30 -r 7"
+    fi
+    $retry sudo docker compose build
     exit_code=""
-    "$thisdir"/retry sudo MOJO_CLIENT_DEBUG=1 docker compose up -d || exit_code=$?
+    $retry sudo MOJO_CLIENT_DEBUG=1 docker compose up -d || exit_code=$?
     if [[ -n $exit_code ]]; then
         echo "docker compose exited with non-zero code $exit_code, showing logs:"
         docker compose logs