Add logs test with OpenTelemetry log receiver

[keiko713]

Follow-up of #544

Here is how it looks with success:

/ $ LOG_OTEL_SERVER=0.0.0.0:4318 /home/pganalyze/collector --test-logs
2024/05/16 03:01:31 I Running collector test with pganalyze-collector 0.56.0
2024/05/16 03:01:31 I [default] Testing log collection (OpenTelemetry Log receiving)...
2024/05/16 03:01:31 I [default] Setting up OTLP HTTP server receiving logs with 0.0.0.0:4318
2024/05/16 03:01:35 I [default]   Log test successful

When the collector is already running well and receiving logs in background, it'll look like the following:

/ $ /home/pganalyze/collector --test-logs
2024/05/16 03:02:24 I Running collector test with pganalyze-collector 0.56.0
2024/05/16 03:02:24 I [default] Testing log collection (OpenTelemetry Log receiving)...
2024/05/16 03:02:24 I [default] Setting up OTLP HTTP server receiving logs with 0.0.0.0:4318
2024/05/16 03:02:34 E [default] ERROR - OpenTelemetry log tail timed out after 10 seconds - did not find expected log event in stream
2024/05/16 03:02:24 I [default] HINT - This error may be a false positive if the collector is also running in the background and receiving logs

[msakrejda]

Thanks for adding this 👍