Add network change monitoring

[breedx-splk]

The instrumentation that reports network changes has not yet been wired up. This adds it to the configuration and enables the instrumentation in the builder's build().

One additional aspect is that the CurrentNetworkProvider now has a setter on the OpenTelemetryRumBuilder. This allows existing components that may rely on this functionality to share the instance. The creation is lazy, so that if the builder user didn't create one, it is created at build time on demand.

I expect this CurrentNetworkProvider sharing to hopefully not be necessary in the long term, but right now there are existing disk buffering implementations (eg. Splunk's distro) that also need to determine information about the current network availability before attempting export.

[LikeTheSalad]

Cool! I'm planning to add some changes in the future to the way the network is monitored due to the deprecated Google APIs issue... But in the meantime, I think it should be fine to use it as it is now.

[breedx-splk]

Yeah, cool, long term I think we'll still need to:

• Consider hiding the CurrentNetworkProvider and provide a more elegant way for users to get notified on otel-compatible network change events.
• Consider if we need to check current network status before attempting to send from disk-buffered telemetry. Could cut down on failures/exceptions/unnecessary attempts and in worse case maybe throwing buffered data away.