Logging Improvements (#88)

This change revamps the internal logging architecture to be more flexible and descriptive. Previously all logs from both llama-swap and upstream services were mixed together. This makes it harder to troubleshoot and identify problems. This PR adds these new endpoints: 

- `/logs/stream/proxy` - just llama-swap's logs
- `/logs/stream/upstream` - stdout output from the upstream server

config.example.yaml

@@ -1,9 +1,9 @@
 # Seconds to wait for llama.cpp to be available to serve requests
 # Default (and minimum): 15 seconds
-healthCheckTimeout: 15
+healthCheckTimeout: 90
 
-# Log HTTP requests helpful for troubleshoot, defaults to False
-logRequests: true
+# valid log levels: debug, info (default), warn, error
+logLevel: info
 
 models:
   "llama":