Set SampleRate for OTLP Logs

[JamieDanielson]

Is your feature request related to a problem? Please describe.

A husky event is an object that contains both Attributes and Sample Rate (and Timestamp but that's irrelevant here).

// Event represents a single Honeycomb event
type Event struct {
	Attributes map[string]interface{}
	Timestamp  time.Time
	SampleRate int32
}

Traces add SampleRate but logs do not.

Describe the solution you'd like

Set SampleRate for logs like we do for traces.