Global trust configuration is generated ipa-adtrust-install script
is run. Add convenience commands to show auto-generated options
like SID or GUID or options chosen by user (NetBIOS). Most of these
options are not modifiable via trustconfig-mod command as it would
break current trusts.
Unit test file covering these new commands was added.
https://fedorahosted.org/freeipa/ticket/3333
