Infer type/version/loader from packwiz

### Enhancement Type

Improve an existing feature

### Describe the enhancement

Currently using packwiz with Quilt for the latest release of Minecraft and the Quilt loader can cause problems because the container sees that the type is set to Quilt, and downloads whichever version of the loader it prefers, which in this case is actually 0.18.x beta, which is incompatible with mods in my packwiz pack. This could be fixed if the version, type and loader version env vars were simply replaced with values read directly from the packwiz pack.

Start by locating the existing packwiz integration and the environment-variable handling for type, version, and loader version. Trace how values are read from a packwiz pack, then verify that compatible values override defaults without breaking other server setups.

Written by the indexing model from the issue text.