Add support for netrc

Description

In a multi-component project, in order to create a hot CI pipeline, a component wants to refer to other components via VCS dependencies, not only via published/released artifacts. In this way, it is possible to continuously integrate develop with develop.

Of course, in an on-premise GitLab, such access requires authentication. In GitLab, to do this, the natural way is to use a Job Token (gitlab-ci-token and ${CI_JOB_TOKEN}). But VCS dependencies does not support environment variables, so, we cannot use something like mydep @ git+https://gitlab-ci-token@${CI_SERVER_HOST}/Group/mydep.git@develop.

Hopefully, pip supports .netrc in order to retrieve the required authentication.

Implementation ideas

One solution is to reuse the implementation of .netrc support in Ansible template, based on envsubst: https://gitlab.com/to-be-continuous/ansible/-/blob/master/templates/gitlab-ci-ansible.yml#L619

Another idea is to hardcode support for GitLab Job Token with: cho -e "machine ${CI_SERVER_HOST}\nlogin gitlab-ci-token\npassword ${CI_JOB_TOKEN}" >> $HOME/.netrc