.gitlab-ci.yml docker login before build

After swapping login information in favour of the vidjilci account,
pulling images was impossible due to authentication issues.
3 jobs for feature-s/docker-login-before-build in 6 minutes and 17 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test Tools
passed #185531
test_tools

00:00:06

 
  Test Unit
passed #185532
web
test_server_unit

00:00:18

 
  Test Functional
passed #185533
docker x86_64
test_server_functional

00:05:52