feat: support WORLD files in compressed tar format (#1297)

tests/setuponlytests/world_from_tgz/docker-compose.yml

@@ -0,0 +1,14 @@
+version: "3"
+
+services:
+  mc:
+    restart: "no"
+    image: ${IMAGE_TO_TEST:-itzg/minecraft-server}
+    environment:
+      EULA: "TRUE"
+      SETUP_ONLY: "TRUE"
+      VERSION: ${MINECRAFT_VERSION:-LATEST}
+      WORLD: /worlds/world-for-testing.tgz
+    volumes:
+      - ./worlds:/worlds:ro
+      - ./data:/data

tests/setuponlytests/world_from_tgz/verify.sh

@@ -0,0 +1 @@
+mc-image-helper assert fileExists world/level.dat