ci: remove unused Docker variables and services

Removes unnecessary Docker variables and services from the CI 
configuration. This streamlines the build process and reduces 
complexity, as these settings are no longer required for the 
pipeline to function correctly.

.gitlab-ci.yml

@@ -2,16 +2,7 @@ stages:
   - build
   - deploy-prod
 
-variables:
-  DOCKER_HOST: tcp://docker:2376
-  DOCKER_TLS_CERTDIR: "/certs"
-  DOCKER_TLS_VERIFY: 1
-  DOCKER_CERT_PATH: "$DOCKER_TLS_CERTDIR/client"
-  DOCKER_DRIVER: overlay2
-
 image: buildtool/build-tools:${BUILDTOOLS_VERSION}
-services:
-  - docker:${DOCKER_DIND_VERSION}
 
 build:
   stage: build