proposal: a new Opentelemetry sampler to support consistent probability sampling

*Title*:
*proposal: a new Opentelemetry sampler to support consistent probability sampling*

*Description*:
A proposal to add a new OTEL sampler to support consistent probability sampling according to OTEL documentation https://opentelemetry.io/docs/specs/otel/trace/tracestate-probability-sampling/#consistent-sampling-decision .

The existing implementations aren't allowing to implement consistent sampling.

The sampler should implement Opentelemetry spec and use `tracestate` header with `ot` context to propagate data required for a consistent probability decision (rejection threshold and randomness value) on each stage (e.g. OTEL collectors or service level samplers)

```
tracing:
provider:
name: envoy.tracers.opentelemetry
typed_config:
"@type": type.googleapis.com/envoy.config.trace.v3.OpenTelemetryConfig
grpc_service: { ... }
sampler:
name: envoy.tracers.opentelemetry.samplers.consistent_probability_based
typed_config:
"@type": type.googleapis.com/envoy.extensions.tracers.opentelemetry.samplers.v3.ConsistentProbabilityBasedSamplerConfig
sampling_probability: 0.1
```

*Relevant Links*:
>Any extra documentation required to understand the issue.
- Opentelemetry consistent sampling documentation https://opentelemetry.io/docs/specs/otel/trace/tracestate-probability-sampling/#consistent-sampling-decision
- Opentelemetry collector probabilistic sampler processor https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/processor/probabilisticsamplerprocessor/README.md

Start with the linked OpenTelemetry consistent sampling specification and the opentelemetry-collector-contrib probabilistic sampler processor README. Use the proposed consistent_probability_based sampler and ConsistentProbabilityBasedSamplerConfig entry points as the scope; done means supporting the specified tracestate ot context data for consistent probability decisions across sampling stages.

Written by the indexing model from the issue text.