Implement Guild Onboarding

[rayakame]

Summary

Basically just support Guild onboarding.

I've already finished this on my old account but that account got suspended before merging😥

Why is this needed?

Because its not implemented yet

Ideal implementation

To be decided.

Checklist

• I have searched the issue tracker and have made sure it's not a duplicate. If it is a follow up of another issue, I have specified it.