add get flash list

app/routers/flash.py

@@ -0,0 +1,17 @@
+import os
+
+from fastapi import APIRouter
+
+import json
+
+router = APIRouter()
+
+@router.get("/get-flash-files")
+async def get_flash_files():
+
+    # Flash files directory
+    FLASH_DIR = os.getenv('FLASH_DIR')
+
+    files_list = os.listdir(FLASH_DIR)
+
+    return {"files":files_list}