Add basic CI/CD functionality

This MR adds a basic CD/CD pipeline, which validates the top-level pipeline.cwl workflow with an example input.

.gitlab-ci.yml

@@ -6,7 +6,7 @@ workflow:
     - when: always
 
 stages:
-  - prepare
+  - build
   - test
 
 include:
@@ -14,11 +14,9 @@ include:
   - template: Security/Dependency-Scanning.gitlab-ci.yml
   - template: Security/Secret-Detection.gitlab-ci.yml
 
-build_ci_runner_image:
-  stage: prepare
-  image: docker
-  tags:
-    - dind
+build-image:
+  stage: build
+  image: docker:latest
   before_script: 
     - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
   script: