Merge branch 'gitlab_pages' into development_version/2.1.7

.gitlab-ci.yml

+image: ruby:2.6
+
+pages:
+  script:
+    - mkdir public
+    - cp -r docs/build/html/* public/
+  artifacts:
+    paths:
+      - public
+  only:
+    - gitlab_pages
\ No newline at end of file