Make S3 optional

app.py

@@ -46,6 +46,7 @@ s.headers.update({
 })
 s.cookies = cookie_jar  # type: ignore
 
+s3_client = None
 if all(key in os.environ for key in [
     'NICONICOGAY_S3_ACCESS_KEY',
     'NICONICOGAY_S3_SECRET_KEY',
@@ -60,8 +61,7 @@ if all(key in os.environ for key in [
         config=BotoConfig(s3={'addressing_style': 'virtual'}),
     )
 else:
-    logger.warning("S3 credentials not provided, exiting")
-    exit(1)
+    logger.warning("S3 credentials not provided. Videos will not be downloaded.")
 
 download_tracker = {
     'active_downloads': 0,