Resolve "Improve pipeline speed"

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Closes #126 (closed)

build/ci/.build-container.yml

 variables:
   DOCKER_TLS_CERTDIR: "/certs"
 
+build_testing:
+  before_script:
+    - echo "override global before script"
+  stage: build
+  allow_failure: false
+  needs: []
+  tags:
+    - shell-builder
+  script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build --build-arg GITLAB_USER=$GO_MODULES_USER --build-arg GITLAB_TOKEN=$GO_MODULES_ACCESS_TOKEN -t registry.code.fbi.h-da.de/cocsn/gosdn:testing_2_${CI_PIPELINE_ID} .
+    - docker push registry.code.fbi.h-da.de/cocsn/gosdn:testing_2_${CI_PIPELINE_ID}
+
 .build: &build
   before_script:
     - echo "override global before script"
@@ -14,7 +27,6 @@ variables:
     - docker build --build-arg GITLAB_USER=$GO_MODULES_USER --build-arg GITLAB_TOKEN=$GO_MODULES_ACCESS_TOKEN --build-arg BUILDARGS=$BUILDARGS -t $DOCKER_IMAGE_SHA .
     - docker push $DOCKER_IMAGE_SHA
     - docker tag $DOCKER_IMAGE_SHA $TAG
-    - docker tag $DOCKER_IMAGE_SHA registry.code.fbi.h-da.de/cocsn/gosdn:${CI_PIPELINE_ID}
     - docker push $TAG
 
 build:develop: