Datapack imports from Modrinth, HTTP(S) and local file ZIPs

Work in progress parked from the working tree so the hydrology merge
could land; amend or squash as needed.

adapters/bukkit/plugin/src/test/java/art/arcane/iris/core/commands/IrisStructureLocateCommandContractTest.java

@@ -205,7 +205,7 @@ public class IrisStructureLocateCommandContractTest {
         assertTrue(method.contains("non-generating structure candidate(s) and their reasons to the server console"));
         assertTrue(method.contains("no chunks were searched"));
         assertTrue(method.indexOf("DatapackIngestService.installed()") > method.indexOf("J.a(() ->"));
-        assertTrue(source.contains("engine.getDimension().getDatapackImports()"));
+        assertTrue(source.contains("DatapackIngestService.configuredImports(engine.getDimension())"));
         assertTrue(source.contains("snapshot.configuredImportUrls().contains(importUrl)"));
         assertTrue(source.contains("engine.getData().getStructureLoader().getPossibleKeys()"));
         assertFalse(method.contains("commandSender.sendMessage(exclusion"));