New channel overview, backups and more security

• NewNew channel overview by category: AI, default or muted per channel
• NewEnable whole categories, even empty ones like tickets
• NewAutomatic backups of server settings with one-click restore
• NewDownload settings as a file and copy them to other servers
• NewAllow or block people per server, with avatar and name
• NewUnlimited role on the RZ Discord is assigned automatically
• ImprovedRole picker with colours and member count
• ImprovedNicer link previews in Discord, also in English
• ImprovedThe bot now knows the shop, credits and unlimited exactly
• FixedWebsite knowledge saves all links again instead of only 3
• FixedImages are recognised reliably again
• SecurityProtection against forged forms and too many requests
• SecurityNew security headers for the panel