Revert "Revert "Adjust portfolio privacy settings. See #933""

This reverts commit 5db509e2ec174bf5407ea91ed812f7fe1dbd58e6.
Revert "Revert "Retitle "Site Visibility" setting section in portfolios as "Private"""

This reverts commit e68f16e298e87ea5232d10a05ce83c69bd70df69.