WL-3097 Check whether a ListItem inherits a role

Define the predicate `inheritRole(String roleId)` on a `ListItem`.
WL-3097 Access options even when ineriting roles
WL-3097 Disable the checkbox for inherited roles

In particular lets make sure that for inherited roles:

 1. the checkbox is checked,
 2. the checkbox is disabled, and
 3. the role has an "Inherited" label before it.
WL-3097 Set access roles even if some are inherited

Before we used to block the save, but that's not relevant now.
Merge pull request #15 from ox-it/WL-3097

WL-3097 Configure access roles even if some are inherited