Clean up after dropping support for Net::IP

[mattias-p]

After we drop support for Net::IP in favor of Net::IP::XS in #1119 there are some things we need to clean up.

We need to take care of dependencies for new installations and upgrades. Also, the whole purpose of Zonemaster::Engine::Net::IP is gone so it should be deprecated and eventually removed.

• The installation instructions should be updated install Net::IP::XS instead of Net::IP. (#1130)
• An upgrade instruction should be added directing users to install Net::IP::XS when upgrading to the new version of Zonemaster::Engine.
• The API documentation for Zonemaster::Engine::Net::IP should state clearly that the module is deprecated and that it will be removed. It should also encourage people to migrate their code to use Net::IP::XS directly instead.

[matsduf]

* The installation instructions should be updated install Net::IP::XS instead of Net::IP.

See #1130.

[ghost]

• The API documentation for Zonemaster::Engine::Net::IP should state clearly that the module is deprecated and that it will be removed.

Done with #1202

[tgreenx]

Solved in release v2023.1 by #1130 and #1202.