Container build without Docker

With this MR we use Kaniko instead of Docker to build our images. This way, we can also build and push them without Docker-in-Docker.

.gitlab-ci.yml

+include:
+  - template: 'Workflows/Branch-Pipelines.gitlab-ci.yml'
+
 stages:
   - build
   - test
@@ -19,6 +22,7 @@ default:
   variables:
     DOCKER_TLS_CERTDIR: "/certs"
 
+
 # Theodolite Helm Chart
 
 lint-helm:
@@ -43,6 +47,11 @@ lint-helm:
   before_script:
     - export GRADLE_USER_HOME=`pwd`/.gradle
     - cd theodolite-benchmarks
+  rules:
+    - changes:
+      - theodolite-benchmarks/**/*
+    - when: manual
+      allow_failure: true
 
 build-benchmarks:
   stage: build
@@ -125,8 +134,6 @@ spotbugs-benchmarks:
     - docker push $CR_HOST/$CR_ORG/$IMAGE_NAME
     - docker logout
   rules:
-    - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $IMAGE_NAME && $JAVA_PROJECT_NAME && $CI_COMMIT_TAG"
-      when: always
     - changes:
       - theodolite-benchmarks/*
       - theodolite-benchmarks/$JAVA_PROJECT_NAME/**/*
@@ -134,7 +141,6 @@ spotbugs-benchmarks:
       - theodolite-benchmarks/flink-commons/**/*
       - theodolite-benchmarks/load-generator-commons/**/*
       if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $IMAGE_NAME && $JAVA_PROJECT_NAME"
-      when: always
     - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $IMAGE_NAME && $JAVA_PROJECT_NAME"
       when: manual
       allow_failure: true
@@ -299,12 +305,9 @@ deploy-theodolite:
     - docker push $CR_HOST/$CR_ORG/theodolite
     - docker logout
   rules:
-    - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $CI_COMMIT_TAG"
-      when: always
     - changes:
       - theodolite/**/*
       if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
-      when: always
     - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
       when: manual
       allow_failure: true
@@ -343,27 +346,39 @@ deploy-theodolite-kaniko:
       allow_failure: true
 
 
-# Theodolite SLO Checker: Lag Trend
+# Theodolite SLO Checker
 
 test-slo-checker-lag-trend:
   stage: test
   needs: []
   image: python:3.7-slim
-  script:
+  before_script:
     - cd slo-checker/record-lag
+  script:
     - pip install -r requirements.txt
     - cd app
     - python -m unittest
+  rules:
+    - changes:
+      - slo-checker/record-lag/**/*
+    - when: manual
+      allow_failure: true
 
 test-slo-checker-dropped-records-kstreams:
   stage: test
   needs: []
   image: python:3.7-slim
-  script:
+  before_script:
     - cd slo-checker/dropped-records
+  script:
     - pip install -r requirements.txt
     - cd app
     - python -m unittest
+  rules:
+    - changes:
+      - slo-checker/dropped-records/**/*
+    - when: manual
+      allow_failure: true
 
 deploy-slo-checker-lag-trend:
   stage: deploy
@@ -380,12 +395,9 @@ deploy-slo-checker-lag-trend:
     - docker push $CR_HOST/$CR_ORG/theodolite-slo-checker-lag-trend
     - docker logout
   rules:
-    - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $CI_COMMIT_TAG"
-      when: always
     - changes:
       - slo-checker/record-lag/**/*
       if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
-      when: always
     - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
       when: manual
       allow_failure: true
@@ -405,12 +417,9 @@ deploy-slo-checker-dropped-records-kstreams:
     - docker push $CR_HOST/$CR_ORG/theodolite-slo-checker-dropped-records-kstreams
     - docker logout
   rules:
-    - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $CI_COMMIT_TAG"
-      when: always
     - changes:
       - slo-checker/dropped-records/**/*
       if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
-      when: always
     - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
       when: manual
       allow_failure: true
@@ -432,12 +441,9 @@ deploy-random-scheduler:
     - docker push $CR_HOST/$CR_ORG/theodolite-random-scheduler
     - docker logout
   rules:
-    - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW && $CI_COMMIT_TAG"
-      when: always
     - changes:
       - execution/infrastructure/random-scheduler/**/*
       if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
-      when: always
     - if: "$CR_HOST && $CR_ORG && $CR_USER && $CR_PW"
       when: manual
       allow_failure: true