mutually_exclusive and required_one_of are only able to check if the parameters
are defined, but not if they are set to "".

Test if the krb5.keytab on the machine is valid and can be used.

options:
  servers:
    description: The FQDN of the IPA servers to connect to.
    required: true
  domain:
    description: The primary DNS domain of an existing IPA deployment.
    required: true
  realm:
    description: The Kerberos realm of an existing IPA deployment.
    required: true
  hostname:
    description: The hostname of the machine to join (FQDN).
    required: true
  kdc:
    description: The name or address of the host running the KDC.
    required: true
  principal:
    description: The authorized kerberos principal used to join the IPA realm.
    required: false
  kinit_attempts:
    description: Repeat the request for host Kerberos ticket X times.
    required: false
    default: 5

returns:
  krb5_keytab_ok:
    description: The flag describes if krb5.keytab on the host is usable.
    returned: always
    type: bool

The use od ipaclient_keytab for ipahost is not correct as the admin keytab
needs to be used here.

For force_join it is also needed to purge the realm information from the
keytab, otherwise new entries will be added with every join.

If a otp has bene generated it is needed to purge the realm from an exising
host keytab. If there is no host keytab or if the keytab is not containing
information about the realm, ipa-rmkeytab will fail and these two errors are
ignored.

With otp usage the user supplied principal may not be used for join.

When ipahost is run to generate an OTP and the host is already existing,
the OTP is properly generated but ipa-join will fail if the host is
already enrolled (ie when it has a keytab).
Add a step calling ipa host-disable to erase OTP and keytab before
requesting an OTP.

If use_otp is not enabled, then the principal will be set to "admin" after
the discovery has been done. If use_otp is enabled, then the princial will
be set to "admin" after the join has been done - as admin will not match
with the otp.

The use of otp can be forced to not transfer the admin password while setting
up the ipa client. Only the one-time-password will be transferred to the
client machine.

ipaclient_password will be overwritten by the otp password.

Also: Add ipaclient_kinit_attempts default value to
roles/ipaclient/defaults/main.yml

The one_of check was using a tuple instead of a list, the check for principal
or keytab has been removed, a new mutually exclusive check for password
xor keytab has been added.

New variables have been added (undefined by default):
  krb5_dns_canonicalize_hostname
  krb5_pkinit_anchors
  krb5_pkinit_pool

These are set according to the ipa version requirements. See
roles/ipaclient/tasks/install.yml

For ipa versions prior to 4.5 it is needed to use ipa-client-install script
as a source for functions. But the script contains a global finally clause
in which the generated ccache file gets removed. Threfore the script is
temporarily copied to ipa_client_install.py and the global finally clause
gets removed from the copy. All this is done in a temporary directory, which
gets removed right after the import has been done.

For ipa versions prior to 4.5 it is needed to use ipa-client-install script
as a source for functions. But the script contains a global finally clause
in which the generated ccache file gets removed. Threfore the script is
temporarily copied to ipa_client_install.py and the global finally clause
gets removed from the copy. All this is done in a temporary directory, which
gets removed right after the import has been done.

A Object called options is generated as ipa-client-install and also
ipaclient/install/client.py functions are using this object.

inspect.argspec is used on configure_krb5_conf to find out if the function
requires configure_sssd as an optional argument or in the options object.

freeipa 4.4 is the first version that supports all needed functions.
Therefore a check has been added to make sure that ipadiscovery fails for
versions before 4.4.

The python bindings of ipa versions before 4.6 are having a different
structure.

ipa_python_version is the version gathered from ipapython.version.NUM_VERSION.
For ipa versions before 3.2.1, the version is generated from
ipapython.version.VERSION because NUM_VERSION changed the format two times
before 3.2.1.

The discovery was not working if a server has been specified. The domain has
been needed additionally. The domain is now gathered from the server name if
it is missing in this case.

- Backup ipa default conf
- Backup krb5.conf

This is needed to be able to use defined and undefined checks.