Fix hev-display build

Previously a couple of missing files were preventing the cmake stage of the build for hev-display. Re-added them and also removed the build for raspi1, since we're targeting raspi v4 only. Also optimised the jobs to prevent multiple docker image pulls cutting the time for compilation to about a sixth of the time, more than the ~ half I expected.

Builds can be triggered by adding a new remote to an instance of Gitlab with a shared runner (gitlab.com / gitlab.cern.ch etc) and pushing there

git remote add personal https://gitlab.cern.ch/dmurray/hev-sw-build
git push personal <branch>