[chestshop] Remove the broken/pointless /chestshop access toggle

/chestshop access (AccessToggle) advertises "Toggle trading at shops you own or have access to", but in PlayerInteract the toggle (!AccessToggle.isIgnoring) only relaxes the access-perms clause — the isOwner(...) clause has no toggle escape, so for shops you own the toggle is a no-op (always blocked). For co-accessed shops, a trade against your own firm/shared account is a self-transfer that nets to nothing yet still writes ledger rows, and Treasury now rejects true self-transfers (wasHandled()==false → goods reversed → cancelled).

Rip the toggle out, keep the underlying guard that blocks trading at your own/accessible shops (sensible — just no opt-out):

• delete commands/AccessToggle.java
• drop the && !AccessToggle.isIgnoring(player) escape in PlayerInteract
• remove Permission ACCESS_TOGGLE enum + Node, TOGGLE_ACCESS_ON/OFF messages + keys, plugin.yml ChestShop.accesstoggle, unregister from command handlers