Add config for Plutonia music tracks

[SirYodaJedi]

Plutonia's tracks are reused from Doom I+II, so they can be pulled from the user's installation of music packs for Doom I and Doom II.

[fragglet]

Thanks. This is unnecessary by design since the configs work based on the hashes of the music lumps. If you have the Doom and Doom II music packs installed, it just works.

This repository is also obsolete.