refactor: remove unnecessary variables and services

Eliminate unused DOCKER_HOST variable and Docker service from CI 
configuration. This simplifies the setup and improves build 
performance by reducing overhead.

.gitlab-ci.yml

@@ -1,15 +1,10 @@
 stages:
   - build
 
-variables:
-  DOCKER_HOST: tcp://docker:2375/
-
 image: buildtool/build-tools:${BUILDTOOLS_VERSION}
 
 build:
   stage: build
-  services:
-  - docker:${DOCKER_DIND_VERSION}
   script:
     - build
     - push