Add and use cleanup_lxc function for system cleanup

Introduced a new cleanup_lxc function in core.func to standardize and enhance system cleanup across scripts. Updated debian.sh and debian-install.sh to use this function instead of inline cleanup commands, improving maintainability and consistency. Also updated author and copyright information.

ct/debian.sh

@@ -1,9 +1,9 @@
 #!/usr/bin/env bash
 source <(curl -fsSL https://git.community-scripts.org/community-scripts/ProxmoxVED/raw/branch/main/misc/build.func)
-# Copyright (c) 2021-2025 tteck
-# Author: tteck (tteckster)
+# Copyright (c) 2021-2025 community-scripts ORG
+# Author: MickLesk (CanbiZ)
 # License: MIT | https://github.com/community-scripts/ProxmoxVED/raw/main/LICENSE
-# Source: https://www.debian.org/
+# Source:
 
 APP="Debian"
 var_tags="${var_tags:-}"
@@ -30,9 +30,10 @@ function update_script() {
     exit
   fi
   msg_info "Updating $APP LXC"
-  $STD apt-get update
-  $STD apt-get -y upgrade
+  $STD apt update
+  $STD apt upgrade -y
   msg_ok "Updated $APP LXC"
+  cleanup_lxc
   exit
 }