Use the new `flagger` package to power the following features flags in the codebase:
- [x] `use_span_metrics`
- [x] `kafka_span_eval`
- [x] `interpolation_enabled`
* feat(telemetry/meter): added base setup for telemetry meter signal
* feat(telemetry/meter): added metadata setup for meter
* feat(telemetry/meter): fix stmnt builder tests
* feat(telemetry/meter): test query range API fixes
* feat(telemetry/meter): improve error messages
* feat(telemetrymeter): step interval improvements
* feat(telemetrymeter): metadata changes and aggregate attribute changes
* feat(telemetrymeter): metadata changes and aggregate attribute changes
* feat(telemetrymeter): deprecate the signal and use aggregation instead
* feat(telemetrymeter): deprecate the signal and use aggregation instead
* feat(telemetrymeter): deprecate the signal and use aggregation instead
* feat(telemetrymeter): cleanup the types
* feat(telemetrymeter): introduce source for query
* feat(telemetrymeter): better naming for source in metadata
* feat(telemetrymeter): added quick filters for meter explorer
* feat(telemetrymeter): incorporate the new changes to stmnt builder
* feat(telemetrymeter): add the statement builder for the ranged cache queries
* feat(telemetrymeter): use meter aggregate keys
* feat(telemetrymeter): use meter aggregate keys
* feat(telemetrymeter): remove meter from complete bools
* feat(telemetrymeter): remove meter from complete bools
* feat(telemetrymeter): update the quick filters to use meter