Add oc_add_gh_team_to_nsp script and rolebinding template

[matthieu-foucault]

This script has to be run manually be someone with admin access to the namespaces. e.g.

./lib/oc_add_gh_team_to_nsp.sh --token <your_gh_token> -t cas-owners -pp 0fad32,09269b,9212c9 -r admin

Todo:

• [x] Add labels to the RoleBinding objects
• [x] Delete RoleBinding objects with the aforementioned labels at the start of the script, to ensure synchronization with GH team

.env file was added to the CAS GGIRCS vault