add: Added .cleanupguilddata command which will delete all guildconfigs, xp stats and other data related to any guild the bot is no longer in. This is a highly destructive and irreversible command.

dev: Added cascade deletes to any tables which have guildconfigs FK, as well as to some other missing places

src/NadekoBot/Db/Models/anti/AntiSpamSetting.cs

@@ -4,8 +4,7 @@
 public class AntiSpamSetting : DbEntity
 {
     public int GuildConfigId { get; set; }
-    public GuildConfig GuildConfig { get; set; }
-
+    
     public PunishmentAction Action { get; set; }
     public int MessageThreshold { get; set; } = 3;
     public int MuteTime { get; set; }