Fixes #5556, #8246, #8299 as they are related

Needs to be merged together with https://github.com/theforeman/hammer-cli/pull/151

- adds better error message when searchable options are missing
- resolves params with array of names to ids
- adds more name parameters to host and hostgroup create/update
`sp_subnet_id` is not writable attribute in host API. Issue for  API docs filed http://projects.theforeman.org/issues/8459