- "krb_principal" can take a list of principals to create or delete.
- "krb_keytab" can take a list of principals to put inside one keytab.
- Move "try_kinit" in module_utils to be used by other modules.

The return code of grep was not checked so nothing was check.

Use a module to check if keytab is working and reuse the same
code used by "krb_keytab".

The new check use the new "try_kinit" which supports checking
multiple principals inside one keytab.

Spnego keytabs need to be created once per machine.

Add support for creating spnego HA keytabs by adding HA addresses
(for example a load balancer) inside the spnego keytab.