add network policy option for gitlab

Summary

• Add network policy toggle for gitlab
• update release tag for gitlab package

Various changes to Gitlab Package:

• network polices
• limit default user permissions
• add helm tests for CI pipelines
• remove unneeded registry.host key in values.yaml
• documentation about backing up the gitlab-rails secret
• ironbank image for praefect

Closes #438
Closes #456 (closed)