ipa-client: Set NIS domain name in the installer

Provides two new options for the ipa-client-install:
    --nisdomain: specifies the NIS domain name
    --no_nisdomain: flag to aviod setting the NIS domain name

In case no --nisdomain is specified and --no_nisdomain flag was
not set, the IPA domain is used.

Manual pages updated.

http://fedorahosted.org/freeipa/ticket/3202
ipa-client-install: Configure sudo to use SSSD as data source

Makes ipa-client-install configure SSSD as the data provider
for the sudo service by default. This behaviour can be disabled
by using --no-sudo flag.

https://fedorahosted.org/freeipa/ticket/3358
ipatests: Add Sudo integration test