ci: remove unused Docker variables and services

Removes unnecessary Docker variables and services from the  
GitLab CI configuration to simplify the build process. This  
streamlines the pipeline and eliminates potential conflicts  
with Docker settings.

.gitlab-ci.yml

@@ -5,15 +5,10 @@ stages:
   - build
   - deploy
 
-variables:
-  DOCKER_HOST: tcp://docker:2375/
-
 image: buildtool/build-tools:${BUILDTOOLS_VERSION}
 
 build:
   stage: build
-  services:
-    - docker:${DOCKER_DIND_VERSION}
   script:
     - build
     - push