Add support for -e IPA_SERVER_IP=no-update.

[adelton]

When an IPv4 address is set using the ipa-server-install's --ip-address parameter and the DNS record gets populated with that value, the current logic in ipa-server-configure-first rewrites that value after the ipa-server-install finishes and then during the subsequent container starts with the current internal IPv4 address of the container. Admins then have to use the IPA_SERVER_IP environment variable to force the value to be left alone.

This PR adds support for IPA_SERVER_IP value no-update, to just leave the DNS records alone during the container startup.

That way, whatever value(s) get set either during the initial ipa-server-install or perhaps manually will not get lost.

[adelton]

Hello @djasa, you've recently contributed #624.

I wonder if the proposed approach in this PR (as an alternative to #617 and #639) would possibly make it easier for your use cases -- be able to disable updates of the IPv4 addresses, and use the general --ip-address approach.

Of course, if you are using the FreeIPA container for some CI setups where you only connect to it from the same host or other containers, the current logic which updates the DNS record to the internal IP address in the container might be fitting your needs best. The PR should not break that functionality.

[djasa]

The IP sync is actually good for my use case but this is surely nice to have.

[adelton]

Added tests, fixed problem with the Kubernetes Pod definition that was uncovered by those tests, merged.