The support for external cert files is not complete yet.

With ansible 2.3.1 it is possible to have one place as an additional utils
module to do all the needed steps to be able to generate the environment for
new and older ipa versions.

The library modules are now a lot smaller.

The minimal ansible version has been increased to 2.3.1.

In the future it might now also be possible to have a special
ansible_ipa_client version for ipa < 4.4 in this utils module.

- Backup ipa default conf
- Backup krb5.conf