Community unlabel command

• There is community issue and MR label for allowlisted labels
• There is community issue and MR unlabel for allowlisted labels
  • Allowlisted labels for @gitlab-bot unlabel same as allowlisted labels for @gitlab-bot label
  • Allow: @gitlab-bot unlabel <label...>
  • Deny: @gitlab-bot unlabel
  • Add to documentation
• Quick actions