Add more features to the staff application automation

[slmnio]

• Add a deny button so the approval button isn't there forever to be clicked on
• Add a check when approving applications through messages that the event is still active before continuing (avoids old messages being clicked on, guess this is superseded by the first one)
• Add a force approve checkmark on Airtable so we can do it without Discord messages
• When editing the message to confirm someone has approved it, use the name of the approver (eg Approved by Solomon)
• Have a channel only be un-approved applications (ie delete the message after approve or deny)

[slmnio]

Deny button will need a bit of a rework of the approval function - needs to be split into decision making and sending and I'm not gonna do it at 8am