Removing the gitlab ci ability.

This would be great once we have a full lab with a server and a couple
testing environments, but for now this would require resources we
can't spare since the gitlab shared runners do not work for both windows
and linux.

.gitlab-ci.yml

@@ -1,14 +0,0 @@
-before_script:
-   - bundle_install
-
-stages:
-   - build
-   - test
-   - deploy
-
-build_linux:
-   stage: build
-   script:
-      - cargo build
-   only:
-      - master