Add `/nuke` command

[alfetopito]

Summary

• Add a command to ban users fitting a criteria: /nuke <user property>
• Should be restricted to users fitting a given role (let's say moderators)

The initial suggestion by mfw78 on Discord is to filter users with the exact same image.
⚠️ Disclaimer: I have not yet tested whether that would work on not

So we can either make a specific command (/nukebyavatar <avatar id>) or make it more generic (/nuke <property> <value>)

Another use case/sub-command is to ban people by username match: /nuke username '*support*'

Notes

The /identify command (#8) will be used to get the user info