Resolve "Improve gitlab pipelines"

Closes #5 (closed)

.gitlab/client.gitlab-ci.yml

-image: node:10
-
-install:
-  stage: client-install
+client-setup:
+  image: node:10
+  stage: setup
   script:
     - cd client
     - npm install
   artifacts:
     name: "artifacts"
     untracked: true
-    expire_in: 60 mins
+    expire_in: 15 mins
     paths:
       - client/.npm/
       - client/node_modules/
 
-test:unit:
-  stage: client-test
+client-linting:
+  image: node:10
+  stage: test
+  script:
+    - cd client
+    - npm run lint
+  dependencies:
+    - client-setup
+
+client-test:
+  image: node:10
+  stage: test
   script:
     - cd client
     - npm run test:coverage
   dependencies:
-    - install
+    - client-setup
   coverage: /All files\s*\|\s*([\d\.]+)/