Replace Zipkin as the default tracing backend for Dapr with Jaeger V2.

[MyMirelHub]

Describe the proposal

Deprecate Zipkin as the default tracing backend for Dapr and replace it with Jaeger V2.

Rationale:

• Jaeger V2 is OTLP-native: Direct protocol support without translation layers, aligning with Dapr's OpenTelemetry integration
• Single binary deployment: Jaeger V2 ships as a single binary (all-in-one), eliminating the complexity that previously made Zipkin the simpler choice
• Industry direction: OpenTelemetry is the standard, and Jaeger V2's native OTLP support future-proofs Dapr's tracing stack
• Reduced maintenance: Consolidating around one tracing backend simplifies documentation, testing, and support

Proposed changes:

1. Replace dapr_zipkin with dapr_jaeger in dapr init
2. Update default tracing configuration to use OTLP endpoint (Jaeger V2) instead of Zipkin
3. Mark Zipkin configuration as deprecated in future versions
4. Update all documentation and quickstarts to use Jaeger V2
5. Provide migration guide for existing Zipkin users

Release Note

RELEASE NOTE: DEPRECATE Zipkin tracing backend in favor of Jaeger V2.