Remove planned deprecated '--sourceaddr' option

[tgreenx]

Purpose

This PR removes planned deprecated --sourceaddr option.

Context

Relates to https://github.com/zonemaster/zonemaster-engine/pull/1343

How to test this PR

There should be no trace in the code, or documentation of the --sourceaddr option.

Also:

$ zonemaster-cli zonemaster.net --sourceaddr 1.2.3.4
Unknown option: --sourceaddr
Run "zonemaster-cli -h" to get the valid options