Add config.yml.example and sets admin permissions
This commit adds the following:
1. Adds update_user method in auth.py to set admin permissions for
new accounts and pre-existing accounts of admin users. It also
clears the permissions when a user is removed from the admin list.
2. A config.yml.example is added to get the admin list in auth.py and ADMINS
3. Adds documentation to create file config.yml using config.yml.example.
4. Adds login to Django Admin Site using OIDC and refactoring login code from