Introduce GitLab CI config for Pages

Build and publish at every commit on master branch

.gitlab-ci.yml

+stages:
+  - build
+  - publish
+
+generate:
+  image: node:16-bullseye-slim
+  stage: build
+  script:
+    - yarn install
+    - yarn generate
+  artifacts:
+    paths:
+      - dist
+    expire_in: 1 week
+  rules:
+    - if: $CI_COMMIT_BRANCH == "master"
+
+pages:
+  stage: publish
+  needs: ["generate"]
+  script:
+    - ls dist