Merge branch 'remove-ci' into 'main'

Delete .gitlab-ci.yml

See merge request !19

.gitlab-ci.yml

-build-job:
-    stage: build
-    tags:
-        - rcds
-    script:
-        - echo "Hello, $GITLAB_USER_LOGIN"
-
-test-job1:
-    stage: test
-    tags:
-        - rcds
-    script:
-        - echo "This job tests something"
-
-test-job2:
-    stage: test
-    tags:
-        - rcds
-    script:
-        - echo "This job tests something, but takes more time than test-job1"
-        - echo "Sleeps for 20 seconds"
-        - sleep 20
-
-deploy-prod:
-    stage: deploy
-    tags:
-        - rcds
-    script:
-        - echo "This job deploys something from $CI_COMMIT_BRANCH branch."
-    environment: production