Fix //snapshot in 1.18 and re-implement biome/entity restoration (#1620)

* Re-add "//snap" and "//snapshot"

* Place code in correct method

* Use CompoundBinaryTags in AnvilChunk18 and implement biome/entity restoration

* Address comments

* Fix biome reading

* Fix retrieval of entities from zipped snapshot world

Co-authored-by: Alex <mc.cache@web.de>

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/PlatformCommandManager.java

@@ -467,7 +467,9 @@ public final class PlatformCommandManager {
             );
             registerSubCommands(
                     "snapshot",
-                    ImmutableList.of("snap"),
+                    //FAWE start - add "/" aliases as well
+                    ImmutableList.of("snap", "/snapshot", "/snap"),
+                    //FAWE end
                     "Snapshot commands for restoring backups",
                     SnapshotCommandsRegistration.builder(),
                     new SnapshotCommands(worldEdit)