Admin moderation/management page

[bricehalder]

Make a new page that is admin-only

• [ ] Add a link to it in the nav bar

This page should be able to:

• [ ] Search for a specific user(s)
  • Filter for usernames matching a substring
  • Extra: add a button to make this accept regex instead of a plain text search. Something like this button
    • This would be helpful for potentially finding inappropriate usernames with common substitutions

For each user entry, we should be able to:

• [ ] Change the username (used for inappropriate names)
• [ ] Email the user
  • This should send from our support@wikispeedruns account
• [ ] Permanently delete their account