CI: add prepare stage

.gitlab-ci.yml

@@ -66,3 +66,27 @@ build:ubuntu-llvm-wip:
   except: [merge_requests]
   extends: .common-build
 
+superbuild-prepare:
+  stage: prepare
+  image: $BUILD_IMAGE_REGISTRY/otb-ubuntu-superbuild-base:18.04
+  before_script:
+# This override the previous before_script
+    - git checkout $CI_COMMIT_REF_NAME
+# We are now doing the git-lfs install
+# This is done after the checkout so we avoid downloading Data
+# But we need it to upload the archive
+    - git-lfs install
+    - git config --global user.email "otbbot@orfeo-toolbox.org"
+    - git config --global user.name "otbbot"
+    - eval $(ssh-agent -s)
+    - ssh-add <(echo "$K8S_SECRET_SSH")
+# This is for debug, we are checking the owner of the ssh key
+# - ssh -o StrictHostKeyChecking=no -T git@gitlab.orfeo-toolbox.org
+  script:
+    - ctest -VV -S CI/prepare_superbuild.cmake -DIMAGE_NAME:string=otb-ubuntu-superbuild-base
+  artifacts:
+    expire_in: 24 hrs
+    paths:
+      # This recovers logs from superbuild build
+      - build/*/*/*/*.log
+