Add build dependencies for apps
- Add a line to the Dockerfile "apt build-dep $app1 $app2 $app3 ..." to install all build dependencies
- Locally test with xfce-build if all apps build (note that xfpmc is vala! and catfish is python! so maybe skip those for now)
- Build/deploy new docker image and
- Add .gitlab-ci.yml files to the apps that build