Add support for TLS/HTTPS REST for southbound A1 interface (and NBIs):

• Leverage existing ONAP cert management approaches
• Install and trust southbound security OWN cert(s)/key(s) in A1 PMS/Policy Management If possible without restart – or else at deployment time/restart​ Existing connections may not be valid/trusted anymore​ What reconfig will be needed in nearrtric/gnb? ​
• Dynamic install and trust southbound security client cert(s) in A1 PMS/Policy Management If possible without restart​ Existing connections may not be valid/trusted anymore​ What reconfig will be needed in nearrtric/gnb?