update knowledgebase

common/docs/knowledgeBase/digitalocean-maintenance.txt

+A. To open/close a port
+=======================
+1. login digital-ocean
+url: https://cloud.digitalocean.com/projects/e8c622a2-ceeb-47c1-a80d-614f419c1cb5/resources?i=940426
+user: ipg.test@ipgallery.com
+password: giptmgr1
+
+2.goto: Networking ==> Firewalls
+  click ipg-demo-fw
+
+3. add new role with the required port
+
+