git: Add '.gitlab-ci.yml' file.

.gitlab-ci.yml

+stages:
+  - build
+  - test
+  - release
+
+build:
+  stage: build
+  script:
+    - echo "TODO build pamhyr"
+
+test:
+  stage: test
+  script:
+    - echo "TODO PAMHYR tests"
+
+# nightly-package:
+#   stage: release
+#   tags:
+#     - release
+#   script:
+#     - cd packages
+#     - ./linux.sh