Add support for python env built by gitlab CI

• Support other ways to configure a custom python environment besides shipping the current conda env
  • use a gitlab CI built packaged python environment using gitlab_project and version (e.g. semantic version or branch name)
  • use a pre-packaged environment by uri, can be local/hdfs file path, or url
• Add gitlab ci pipline to create a packaged python env of wmfdata itself for development