Invitation improvements

Adding a way to track who sent the invite and who used that invite

Also a setting that disables invites made by people who aren't on the server anymore (for whatever reason) would also be a big help in keeping track of invites

A default invite setting would also be nice eg. the default invite for my server by default has a maximum of 1 use and never expires and has temporary membership enabled, rather than 5 uses and 24 hours
also having a different default if it's sent on a server (to avoid raids and such) would be nice too