Added CI configuration

.gitlab-ci.yml

+image: openjdk:17-alpine
+
+variables:
+  GRADLE_OPTS: "-Dorg.gradle.daemon=false"
+
+before_script:
+  - export GRADLE_USER_HOME=`pwd`/.gradle
+
+cache:
+  paths:
+    - .gradle/wrapper
+    - .gradle/caches
+
+stages:
+  - build
+  - test
+
+build:
+  stage: build
+  script: ./gradlew jar
+  cache:
+    key: "$CI_COMMIT_REF_NAME"
+    policy: push
+    paths:
+      - build
+      - .gradle
+    artifacts:
+      paths:
+        - build/lib/*.jar
+
+test:
+  stage: test
+  script: ./gradlew test
+  artifacts:
+    when: always
+    reports:
+      junit: build/test-results/test/**/TEST-*.xml
+  cache:
+    key: "$CI_COMMIT_REF_NAME"
+    policy: pull
+    paths:
+      - build
+      - .gradle
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