[Enhancement] Simplify Account Linking Process

[Ethan]

Hey there! So, I noticed that bind codes can be quite complex and make linking accounts more difficult than necessary. My suggestion is to switch to a simpler system where users can just run /mgb link in Minecraft, then use /mgb link (username) on Guilded, and finally confirm with /mgb confirm in Minecraft. This would make connecting accounts much easier. Best regards.

[MCUmbrella]

I've made the bind code simpler in the latest commit. Have a try.