Refactor CNB command to improve configuration handling and add default keep.json

- Changed import of 'path' module to use default import syntax.
- Updated 'live' command to accept a configuration file path with higher priority than JSON input.
- Removed stdin reading for JSON input; now reads directly from the specified config file.
- Simplified error handling for JSON parsing and configuration validation.
- Enhanced keepAlive creation by removing unnecessary callbacks and enabling debug mode.
- Added default keep.json file with example configuration.

keep.json

@@ -0,0 +1,5 @@
+{
+  "wss": "wss://cnb-pf8-1jhgvbrkm-001.cnb.space:443/stable-3c0b449c6e6e37b44a8a7938c0d8a3049926a64c?reconnectionToken=3d90027f-b2b1-4c60-a3b4-f061b75ec073&reconnection=false&skipWebSocketFrames=false",
+  "cookie": "orange:workspace:cookie-session:cnb-pf8-1jhgvbrkm-001=9cc870da-d3d5-44ee-afdc-7498e1111186",
+  "url": "https://cnb-pf8-1jhgvbrkm-001.cnb.space/?folder=/workspace"
+}