[RN] Move systems deprecated in 7.4.0.Beta to unsuported in 7.4.0

Some of the 3rd party systems that we have in deprecated section in Release Notes should be moved to Unsupported features.

The list:

• IBM DB2 11.1 (was replaced with DB2 11.5 as per EAP7-1632)
• PostgreSQL / EnterpriseDB 11 (was replaced with PostgreSQL 13.2 and EnterpriseDB 13.1 as per EAP7-1489)
• MariaDB 10.1(replaced with 10.3 as per EAP7-1555)
• MS SQL 2017 (replaced with MS SQL 2019 as per EAP7-1442)

• Red Hat Directory Server 10.0 and Red Hat Directory Server 10.1 (replaced with versions 10.6 and 11.3)