Remove cobertura reports from .gitlab-ci.yml files

src/automation/.gitlab-ci.yml

src/compute/.gitlab-ci.yml

src/context/.gitlab-ci.yml

src/dbscanserving/.gitlab-ci.yml

src/device/.gitlab-ci.yml

src/interdomain/.gitlab-ci.yml

src/l3_attackmitigator/.gitlab-ci.yml

src/l3_centralizedattackdetector/.gitlab-ci.yml

src/l3_distributedattackdetector/.gitlab-ci.yml

src/monitoring/.gitlab-ci.yml

src/opticalattackmitigator/.gitlab-ci.yml

src/opticalcentralizedattackdetector/.gitlab-ci.yml

src/service/.gitlab-ci.yml

src/webui/.gitlab-ci.yml