[ci] #388: Add image generation build automation

Introduce Dockerfile based on latest Python available
Install silkaj and make it available to the CLI

Manual triggered job to generate the image
Definition as an extensible job for future usages
Rename stage

.gitlab-ci.yml

 stages:
   - checks
   - tests
-  - publish
+  - package
   - coverage
 
 variables:
@@ -76,8 +76,30 @@ tests-3.9:
   variables:
     PYTHON_VERSION: "3.9"
 
+.container:
+  stage: package
+  tags: [docker]
+  image: docker:latest
+  services:
+  - docker:dind
+  script:
+    - docker login -u "gitlab-ci-token" -p "$CI_BUILD_TOKEN" $CI_REGISTRY
+    - docker build --pull -t "$CI_REGISTRY_IMAGE:$IMAGE_TAG" .
+    - docker login -u "gitlab-ci-token" -p "$CI_BUILD_TOKEN" $CI_REGISTRY
+    - docker tag "$CI_REGISTRY_IMAGE:$IMAGE_TAG" "$CI_REGISTRY_IMAGE:$IMAGE_TAG"
+    - docker push "$CI_REGISTRY_IMAGE:$IMAGE_TAG"
+    - docker tag "$CI_REGISTRY_IMAGE:$IMAGE_TAG" "$CI_REGISTRY_IMAGE:latest"
+    - docker push "$CI_REGISTRY_IMAGE:latest"
+
+container:
+  extends: .container
+  variables:
+    IMAGE_TAG: "dev"
+  rules:
+    - when: manual
+
 pypi_test:
-  stage: publish
+  stage: package
   rules:
     - if: $CI_COMMIT_TAG
       when: manual
@@ -86,7 +108,7 @@ pypi_test:
     - poetry publish --build --username $PYPI_TEST_LOGIN --password $PYPI_TEST_PASSWORD --repository pypi_test
 
 pypi:
-  stage: publish
+  stage: package
   rules:
     - if: $CI_COMMIT_TAG
       when: manual

Dockerfile

+FROM registry.duniter.org/docker/python3/poetry/3.9:latest
+
+WORKDIR /silkaj
+
+# Install Silkaj
+RUN poetry install
+
+# Set up alias to directly get silkaj command
+# https://stackoverflow.com/a/3638886
+RUN printf '#!/bin/bash\npoetry run silkaj "$@"' > /usr/bin/silkaj && \
+    chmod +x /usr/bin/silkaj
+
+CMD ["/usr/bin/silkaj"]