Use ippserver from ipp.rs

[LegNeato]

It would be great to set up a fake printer for tests, as some tests (like printing!) may cause real-world changes and different developers or CI could have different printers defined.

Looks like https://github.com/dremon/ipp.rs has some server support we could possibly leverage. See https://github.com/dremon/ipp.rs/blob/master/examples/ippserver.rs