Add Web UI counterpart of following CLI commands:
* trust-fetch-domains Refresh list of the domains associated with the trust
* trustdomain-del Remove infromation about the domain associated with the trust.
* trustdomain-disable Disable use of IPA resources by the domain of the trust
* trustdomain-enable Allow use of IPA resources by the domain of the trust
* trustdomain-find Search domains of the trust
https://fedorahosted.org/freeipa/ticket/4119