Add FreeIPA enrollment template

Add FreeIPA enrollment template

This is based on previous work [1] and it's what I've been using to
test the TLS-everywhere work.

This introduces a template that will run on every node to enroll
them to FreeIPA and acquire a ticket (authenticate) in order to be
able to request certificates.

Enrollment is done via the ipa-client-install command and it does
the following:

* Get FreeIPA's CA certificate and trust it.
* Authenticate to FreeIPA using an OTP and get a kerberos keytab.
* Set up several configurations that are needed for FreeIPA (sssd,
  kerberos, certmonger)

The keytab is then used to authenticate and get an actual TGT
(Ticket-Granting-Ticket) from Kerberos

The previous implementation used a PreConfig hook, however, here it
was modified to use NodeTLSCAData. This has the advantage that it
runs on every node as opposed to the PreConfig hook where we had to
specify the role type so it's a usability improvement. And, on the
other hand, this does set up necessary things for the usage of
FreeIPA as a CA, such as getting the certificate and enrolling to the
CA.

[1] https://github.com/JAORMX/freeipa-tripleo-incubator

bp tls-via-certmonger

Change-Id: Iac94b3b047dca1bcabd464ea8eed6f1220c844f1