💡 [REQUEST] - Add OpenTelemetry Exporter plugin

### Summary

It would be useful to be able to export SLO reports to OpenTelemetry. I've already done some initial work, but ran into a stumbling block when trying to leverage the existing prometheus exporter as a template. The prometheus exporter creates a Gauge to build the time_series. OpenTelemetry says that prometheus gauges must be converted to OTLP Gauges. Unfortunately, at the moment, OpenTelemetry only supports async gauges, while slo-generator's design calls for a synchronous gauge. I'm currently looking at ways to wrap the async gauge to make it synchronous.

### Basic Example

In the case of writing to Grafana Mimir, it would provide a future-facing alternative to pushgateway or remote write. Ideally both grpc and http would be supported.

### Screenshots

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### Drawbacks

It would add more code to slo-generator that would need to be maintained.

### Unresolved questions

_No response_

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct