Remove the BungeeCord cross-server shop-notification integration

The BungeeCord messaging forwarded shop-sale notifications to an owner logged into a different backend server behind a proxy. Hibernia isn't a multi-backend proxied network, so this was dead upstream machinery — send-only, no receiver, gated off by default.

Ripped out completely:

• Deleted services/BungeeMessenger (the extracted messenger).
• TransactionService.sendMessageToOwner / sendTradeMessage: the offline-owner fallback branch (bungee.send) is gone — an owner not on this server simply gets no notification. Removed the now-dead playerName param from sendTradeMessage.
• ShowItemHook.sendMessage: dropped the bungee fallback branch and the now-dead playerName overload/param; callers (InfoService ×2, TransactionService) updated.
• ChestShop.java: removed registerPluginMessagingChannels() (the outgoing BungeeCord channel) + the 2 bStats charts.
• ChestShopConfiguration + config.yml: removed BUNGEECORD_MESSAGES.

Zero bungee references remain. :chestshop:build green; server enables cleanly; ChestShop integration suite 42/42.