Add feature parity with datapack handling

### Enhancement Type

Improve an existing feature

### Describe the enhancement

For datapacks, add the functionality to map a "datapacks" directory that would be automatically imported to the $WORLD/datapacks folder.

Essentially, add parity between datapacks and the current mods/plugins functionality.

This is currently achieved by manually symlinking the folder, but it would be great to have the same functionality for simplicity's sake.

Thanks for a great container!

Search the repository for the existing mods/plugins directory handling and inspect the startup entry points that perform those mappings. Add equivalent handling for a datapacks directory, then verify that its contents are imported into $WORLD/datapacks and that existing mods/plugins behavior remains unchanged.

Written by the indexing model from the issue text.