Add a /clearalts command to clear player alts

[TBG1000]

Describe the feature you'd like Command: /clearalts Accessible to Senior Moderators and above, this command would be useful for clearing long lists of alternate accounts that pile up after VPN usage or issues with Minehut's IP masking system.

Usefulness of the feature Currently, it is only possible to clear the alts of a player by requesting an Administrator to do so. By having this command, it would eliminate the need of doing so. Additionally, it would help in the long run to prevent confusion among Ban Evasion punishments and appeals, especially those caused by VPN usage.

Additional context

1. Player joins the server while using a VPN, gets linked to multiple banned accounts.
2. Player gets incorrectly banned for Ban Evasion.