Support conversion of non-string LogRecord.attributes values and non-dictionary LogRecord.body values

[DylanRussell]

#376 - currently my PR only converts LogRecord.attributes that are strings and LogRecord.body's that are maps.

This issue is to track converting other types like the go collector does:
https://github.com/GoogleCloudPlatform/opentelemetry-operations-go/blob/main/exporter/collector/logs.go#L348
https://github.com/GoogleCloudPlatform/opentelemetry-operations-go/blob/main/exporter/collector/logs.go#L503-L524