FreeIPA 4.8.7 introduced an option to rename an existing hostgroup.
This patch adds support for renaming hostgroups if the option is
available on installed IPA version.

A new state `renamed` and a new option `rename` (alias: `new_name`)
was added to module `ipahostgroup` to allow renaming of host groups.

The implemented behavior is:
* Rename if `name` exists and `rename` doesn't.
* Do nothing if `name` does not exist and `rename` does, or if
  `name` equals to `rename`. (result.changed is False)
* Fail if neither or both `name` and `rename` exist.