Merge branch 'st-970-add-image-tests' into 'master'

.gitignore

.gitlab-ci.yml

Makefile

images/ska-tango-images-pytango-builder-alpine/Dockerfile

images/ska-tango-images-pytango-runtime-alpine/Dockerfile

images/ska-tango-images-tango-cpp-alpine/Dockerfile

images/ska-tango-images-tango-db-alpine/Dockerfile

images/ska-tango-images-tango-db-alpine/run.sh

images/ska-tango-images-tango-db/Dockerfile

images/ska-tango-images-tango-dependencies-alpine/Dockerfile

...-dsconfig-alpine/ska-tango-images-tango-dsconfig/.release

...sconfig-alpine/ska-tango-images-tango-dsconfig/Dockerfile

images/ska-tango-images-tango-itango-alpine/Dockerfile

images/ska-tango-images-tango-itango-alpine/requirements.txt

images/ska-tango-images-tango-java-alpine/Dockerfile

images/ska-tango-images-tango-rest-alpine/.release

images/ska-tango-images-tango-rest-alpine/Dockerfile

images/ska-tango-images-tango-rest-alpine/supervisord.conf

...a-tango-images-tango-rest-alpine/tango_register_device.sh

tests/post-deployment/features/tango_tools.feature