feat: add the ability to log into a registry on a per-app basis

Closes #5324

plugins/git/git-from-image

@@ -26,6 +26,10 @@ trigger-git-git-from-image() {
   echo "FROM $DOCKER_IMAGE" >>"$TMP_WORK_DIR/Dockerfile"
   echo "LABEL com.dokku.docker-image-labeler/alternate-tags=[\\\"$DOCKER_IMAGE\\\"]" >>"$TMP_WORK_DIR/Dockerfile"
 
+  local DOCKER_CONFIG
+  DOCKER_CONFIG="$(fn-registry-docker-config "$APP")"
+  [[ -n "$DOCKER_CONFIG" ]] && export DOCKER_CONFIG
+
   if [[ "$("$DOCKER_BIN" image ls -q "$DOCKER_IMAGE" 2>/dev/null)" == "" ]]; then
     dokku_log_info1 "Pulling image"
     if ! "$DOCKER_BIN" image pull "$DOCKER_IMAGE"; then