ST-854: Migrate tango examples to poetry
- add missing needed packages to documentation
- change docker image build steps
- add needed unspecified python requirements
- add poetry and poetry project config
- remove requirements.txt
- refactor gitlab-ci yaml
Note: Docker image building rellies on a base image with uneeded/outdated python packages installed (this is due to these images being built with system level pip install)
Note: pytango-builder seem to have the incorrect permissions set. Need to be root to change anything outside HOME
** Future work: It seems extremely wastefull to be building packages and dependencies at least 3 times to do the same. Maybe re-use the build to do the linting and unti testing.**