Adds pages CI, `.gitignore`s `.DS_Store`

.gitignore

 *.class
+.DS_Store

.gitlab-ci.yml

+image: eclipse-temurin:11
+
+pages:
+  tags:
+    - Pages
+  only:
+    - main
+  script:
+    - javac *.java
+    - java GenerateSite
+    - mkdir public
+    - mv index.html public
+    - mv assets public
+    - mv fonts public
+    - mv images public
+    - mv products public
+    - mv staff public
+  artifacts:
+    paths:
+      - public