ECLOUD-146, ECLOUD-132: Refactored invite and leave service functions
ECLOUD-146, ECLOUD-132: Refactored invite and leave service functions

MaritimeCloud/MaritimeCloudPortalTestbed,MaritimeCloud/MaritimeCloudPortalTestbed,MaritimeCloud/MaritimeCloudPortalTestbed,MaritimeCloud/MaritimeCloudPortalTestbed