update code structure and get session on each query

app/config.py

@@ -0,0 +1,9 @@
+import os
+
+
+class Config:
+    LISTEN_ADDRESS = os.getenv("LISTEN_ADDRESS", "0.0.0.0")
+    LISTEN_PORT = int(os.getenv("LISTEN_PORT", "8080"))
+    DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///./mpv.db")
+    MPV_SOCKET = os.getenv("MPV_SOCKET", "/tmp/mpvsocket")
+    LOGLEVEL = os.getenv("LOGLEVEL", "INFO").strip().upper()