Deprecate zipkin exporter #7863
Description
Zipkin exporter is deprecated in the spec: open-telemetry/opentelemetry-specification#4715
We should deprecate our implementation.
When the spec deprecated jaeger, we made the decision to stop publishing our jaeger component after being deprecated for some period of time. The idea is that users could use jaeger indefinitely, but without security fixes and bugfixes.
In practice, I think we botched this because components like the jaeger exporter can dependent / use *.internal.* APIs from other components which may break over time. This is convenient from the standpoint of maintainers, but necessitates version alignment between components published from opentelemetry-java. See #6970 for solving this problem general.
For zipkin, as a prerequisite to eventually stopping publishing, I think we need to make sure it only depends on stable APIs from other components. This will ensure it can be used indefinitely, albeit without bugfixes / security patches.