[FEATURE REQUEST] Add Baggage Support

The Dapr runtime has recently [added support for baggage propagation](https://github.com/dapr/dapr/pull/8649). [Here is the docs PR for reference as well](https://github.com/dapr/docs/pull/4609). Baggage is a mechanism to propagate key-value pairs across service boundaries, which is useful for passing contextual information through distributed traces.

We should add a new function that users can use to add baggage propagation support, working for **both** gRPC and HTTP. This would enable users to provide baggage without having to import OpenTelemetry themselves.

[consumer code _example_](https://github.com/dapr/go-sdk/issues/718)

We should have tests for both gRPC + HTTP for this functionality.

RELEASE NOTE: **ADD** Baggage Support

首先审查消费者代码示例以及 SDK 现有的 gRPC 和 HTTP 传播支持。为两种传输添加所请求的面向用户的 baggage 函数，然后添加并运行涵盖通过 gRPC 和 HTTP 进行 baggage 传播的测试。

由索引模型根据 Issue 内容生成。