Migrate CI to GitLab, clean up Dockerfile and repo

.gitlab-ci.yml

@@ -0,0 +1,31 @@
+stages:
+  - test
+  - publish
+
+variables:
+  GOLANG_VERSION: "1.24"
+
+default:
+  image: golang:${GOLANG_VERSION}
+
+test:
+  stage: test
+  script:
+    - go test ./...
+
+docker:
+  stage: publish
+  image: docker:latest
+  services:
+    - docker:dind
+  variables:
+    DOCKER_BUILDKIT: "1"
+  before_script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+  script:
+    - docker build -t $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG .
+    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG
+    - docker tag $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG $CI_REGISTRY_IMAGE:latest
+    - docker push $CI_REGISTRY_IMAGE:latest
+  rules:
+    - if: $CI_COMMIT_TAG