Remove docker and shell lint from .gitlab-ci.yml

.gitlab-ci.yml

-shellcheck:
-  image: tecnalia-docker-dev.artifact.tecnalia.com/koalaman/shellcheck-alpine
-  script: shellcheck deploy/base/ros_entrypoint.bash scripts/*sh
-  tags:
-    - docker
-
-# The ignored rules in hadolint checks are
-# DL3006 Always tag the version of an image explicitly
-#   One of the Dockerfiles uses a temporary image which isn't important to tag
-#   and the other uses a tagged image through an ARG, which apparently is not
-#   properly recognized.
-# DL3008 Pin versions in apt-get install
-#   A bit overkill
-dockerfiles:
-  image: tecnalia-docker-dev.artifact.tecnalia.com/hadolint/hadolint:latest-debian
-  script:
-    - RET=0
-    - hadolint --ignore DL3006 --ignore DL3008 --ignore DL3059 deploy/base/Dockerfile || RET=1
-    - hadolint --ignore DL3006 --ignore DL3008 --ignore DL3059 deploy/dev/Dockerfile || RET=1
-    - exit $RET
-  tags:
-    - docker
-
 yamllint:
   image: tecnalia-docker-dev.artifact.tecnalia.com/sdesbure/yamllint
   script: yamllint $(find . -name '*.yml' -o -name '*.yaml')