Allow to define a application-local role without any realm role

[adrienlauer]

Application roles are mapped to roles given by the security Realm. For instance, LDAP realm can provide some roles which in turn are giving application-local roles. We need to add the ability to specify an application role that is always given to any user.

This could be a ConfigurationRoleMapping specific feature which could be configured like this:

[org.seedstack.seed.security.roles]
guest = *