Rework save format and punishment manager

- Punishments are now saved as JSON in files named after their targets
- Each punishment type now has its own Java class
- Each file contains a list of JSON objects that is updated every time something changes (e.g. player muted, banned or unbanned)
- Punishments have a unique ID now; if something changes, the new version is added to the list and overwrites the old version
- 'Undo' has been renamed to 'cancel'
- You can no longer mute or ban players if they are already muted or banned

src/main/java/de/shiewk/smoderation/paper/punishments/Mute.java

@@ -0,0 +1,34 @@
+package de.shiewk.smoderation.paper.punishments;
+
+import de.shiewk.smoderation.paper.util.SerializationHelper;
+import org.jspecify.annotations.NonNull;
+
+import java.util.UUID;
+
+public class Mute extends TimedPunishment {
+
+    public Mute(UUID id, long timestamp, UUID issuer, UUID target, String reason, long duration, UUID cancelledBy) {
+        super(id, "mute", timestamp, issuer, target, reason, duration, cancelledBy);
+    }
+
+    public Mute(UUID id, long timestamp, UUID issuer, UUID target, String reason, long duration) {
+        this(id, timestamp, issuer, target, reason, duration, null);
+    }
+
+    public static class Factory implements PunishmentFactory<Mute> {
+
+        @Override
+        public @NonNull Mute deserialize(SerializationHelper helper) {
+            return new Mute(
+                    helper.getUUID("id"),
+                    helper.getLong("timestamp"),
+                    helper.getUUID("issuer"),
+                    helper.getUUID("target"),
+                    helper.getString("reason"),
+                    helper.getLong("duration"),
+                    helper.getUUID("cancelledBy", null)
+            );
+        }
+
+    }
+}