Added placeholder for lastName and role addition functionality

Try to rebase

frontend/pshared/lib/data/mapper/invitation/invitation.dart

@@ -20,6 +20,7 @@ extension InvitationModelMapper on Invitation {
     content: InvitationContentDTO(
       email: content.email,
       name: content.name,
+      lastName: content.lastName,
       comment: content.comment,
     ),
     isArchived: isArchived,
@@ -40,6 +41,7 @@ extension InvitationDTOMapper on InvitationDTO {
     content: InvitationContent(
       email: content.email,
       name: content.name,
+      lastName: content.lastName,
       comment: content.comment,
     ),
     isArchived: isArchived,