feat: Always use HLS session keys to improve player startup performan…

…ce (#181)

Since we don't support key rotation, adding this argument is safe, and it also helps ShakaPlayer reduce startup latency, as well as helping a lot in the case where HLS identity is used.

streamer/packager_node.py

@@ -250,6 +250,7 @@ def _setup_encryption(self) -> List[str]:
       '--protection_scheme',
       encryption.protection_scheme.value,
       '--clear_lead', str(encryption.clear_lead),
+      '--create_session_keys',
     ])
 
     if encryption.protection_systems: