Economy fix https://github.com/leothawne/LTItemMail/commit/139ef9c74d1ab68ef07801ed8e47e7ecd5248f96

Introducing a mailbox storage system!
Compatible with MC 1.13 - 1.20.4 (Java 8+)

New player commands:
/itemmail list - List new/pending mailboxes.
/itemmail open <mailbox id> - Open a pending mailbox.

New admin commands:
/itemmailadmin list <player> - List opened mailboxes of a specific player.
/itemmailadmin recover <mailbox id> - Recover lost items from an opened mailbox.

Changes:
https://github.com/leothawne/LTItemMail/commit/90597d08f08f5daafafbdb5d9aee43dde9822701
https://github.com/leothawne/LTItemMail/commit/c77d2407fbf64a26a064342cee6dfb39727d8559