Remove GitLab CI configuration

- Removes the .gitlab-ci.yml file.
- This file was used for automated builds and deployments.
- The project no longer requires these automated processes.

.gitlab-ci.yml

@@ -1,30 +0,0 @@
-image: alpine:latest
-
-stages:
-  - test
-  - deploy
-
-test_build:
-  stage: test
-  image: klakegg/hugo:0.111.3-ext-alpine-ci
-  script:
-    - hugo version
-    - hugo --minify
-  only:
-    - merge_requests
-    - master
-
-deploy:
-  stage: deploy
-  before_script:
-    - 'command -v ssh-agent >/dev/null || ( apk add --update openssh )'
-    - eval $(ssh-agent -s)
-    - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add -
-    - mkdir -p ~/.ssh
-    - chmod 700 ~/.ssh
-    - ssh-keyscan $SSH_HOST >> ~/.ssh/known_hosts
-    - chmod 644 ~/.ssh/known_hosts
-  script:
-    - ssh -p $SSH_PORT $SSH_USER@$SSH_HOST "cd repo && git stash && git pull --force origin master && ./build.sh"
-  only:
-    - master