Add reference solution for exercise 1 in episode 7

* Add reference solution for exercise 1 in episode 7 regarding using
includes to restructure the CI pipeline and splitting it up into
multiple files.

.gitlab-ci.yml

@@ -5,15 +5,8 @@
 
 ---
 
-stages:
-  - lint
-  - build
-  - test
-  - run
-
 default:
-  image: python:3.11
-  interruptible: true
+  image: python:3.9
 
 .install_dependencies:
   before_script:
@@ -23,57 +16,12 @@ default:
 .compiler_versions:
   parallel:
     matrix:
-      - VERSION: [ "11", "12" ]
-
-license_compliance:
-  stage: lint
-  before_script:
-    - pip install --upgrade pip
-    - pip install reuse
-  script:
-    - reuse lint
-  interruptible: true
-
-lint:
-  stage: lint
-  before_script:
-    - pip install --upgrade pip
-    - pip install cpplint
-  script:
-    - cpplint --recursive src/ tests/
-
-build:gcc:
-  extends:
-    - .install_dependencies
-    - .compiler_versions
-  stage: build
-  image: gcc:${VERSION}
-  script:
-    - cmake -S . -B build_gcc_${VERSION}
-    - cmake --build build_gcc_${VERSION}
-  artifacts:
-    paths:
-      - build_gcc_${VERSION}
-
-test:gcc:
-  extends:
-    - .install_dependencies
-    - .compiler_versions
-  stage: test
-  image: gcc:${VERSION}
-  script:
-    - cd build_gcc_${VERSION} && ctest
-  needs:
-    - job: "build:gcc"
-      artifacts: true
+      - VERSION: [ "10", "11", "12" ]
 
-run:
-  stage: run
-  image: gcc:12
-  script:
-    - ./build_gcc_12/bin/helloWorld
-  needs:
-    - job: "build:gcc"
-      artifacts: true
+include:
+  - local: ".gitlab/ci/lint.gitlab-ci.yml"
+  - local: ".gitlab/ci/build.gitlab-ci.yml"
+  - local: ".gitlab/ci/test.gitlab-ci.yml"
+  - local: ".gitlab/ci/run.gitlab-ci.yml"
 
 ...

.gitlab/ci/build.gitlab-ci.yml

+# SPDX-FileCopyrightText: 2022 Helmholtz Centre for Environmental Research (UFZ)
+# SPDX-FileCopyrightText: 2022 Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
+#
+# SPDX-License-Identifier: MIT
+
+---
+
+build:gcc:
+  image: gcc:${VERSION}
+  extends:
+    - .install_dependencies
+    - .compiler_versions
+  script:
+    - cmake -S . -B build_gcc_${VERSION}
+    - cmake --build build_gcc_${VERSION}
+  artifacts:
+    paths:
+      - build_gcc_${VERSION}
+  needs: ["lint"]
+  interruptible: true
+
+...

.gitlab/ci/lint.gitlab-ci.yml

+# SPDX-FileCopyrightText: 2022 Helmholtz Centre for Environmental Research (UFZ)
+# SPDX-FileCopyrightText: 2022 Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
+#
+# SPDX-License-Identifier: MIT
+
+---
+
+license_compliance:
+  before_script:
+    - pip install --upgrade pip
+    - pip install reuse
+  script:
+    - reuse lint
+  interruptible: true
+
+lint:
+  before_script:
+    - pip install --upgrade pip
+    - pip install cpplint
+  script:
+    - cpplint --recursive src/ tests/
+  interruptible: true
+
+...

.gitlab/ci/run.gitlab-ci.yml

+# SPDX-FileCopyrightText: 2022 Helmholtz Centre for Environmental Research (UFZ)
+# SPDX-FileCopyrightText: 2022 Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
+#
+# SPDX-License-Identifier: MIT
+
+---
+
+run:
+  image: gcc:11
+  script:
+    - cd build_gcc_11/bin/ && ./helloWorld
+  dependencies: ["build:gcc"]
+  needs: ["build:gcc", "test:gcc"]
+  interruptible: true
+
+...

.gitlab/ci/test.gitlab-ci.yml

+# SPDX-FileCopyrightText: 2022 Helmholtz Centre for Environmental Research (UFZ)
+# SPDX-FileCopyrightText: 2022 Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
+#
+# SPDX-License-Identifier: MIT
+
+---
+
+test:gcc:
+  image: gcc:${VERSION}
+  extends:
+    - .install_dependencies
+    - .compiler_versions
+  script:
+    - cd build_gcc_${VERSION} && ctest
+  dependencies: ["build:gcc"]
+  needs: ["build:gcc"]
+  interruptible: true
+
+...