Contact group management

• POSTCreate a contact group/api/v2/contact-groupscontacts:contacts.write
• PUTUpdate a contact group/api/v2/contact-groups/{contactGroupId}contacts:contacts.write
• GETList contact groups/api/v2/contact-groupscontacts:contacts.read
• GETGet a contact group/api/v2/contact-groups/{contactGroupId}contacts:contacts.read
• DELETEDelete a contact group/api/v2/contact-groups/{contactGroupId}contacts:contacts.write