[RC-2813] go wrapper

[mellon85]

Notes

you can check the coverage with

cargo build
cd wrapper/go
go test -v -cover -coverprofile=coverage.out -tags=test_helpers ./...
go tool cover -func=coverage.out | grep -v internal

Commits

• feat: add Go bindings for libdd-rc (74cba55)

      Add comprehensive Go bindings for the Datadog Remote Configuration
      X509 client library with both high-level and low-level APIs.
      
      High-level API features:
      - Context support for cancellation and timeouts
      - Idiomatic Go error handling
      - Thread-safe operations with proper locking
      - Lifecycle validation to prevent misuse
      - Sender interface for flexible I/O handling

[domodwyer]

🎉

Quick look over the layout - I'll check the go code after!

[domodwyer]

I pushed these changes:

• ci: install protoc-gen-go in build image (08f1f7c)

• chore: do not check in generated code (2513d27)

• ci: simplify and normalise Go workflows (cf6f2af)

  Changes:
  
      * Use build image w/ pre-installed dependencies.
      * Use reusable cache action instead to avoid trashing cache.
      * Build dev version of FFI harness (faster, more assertions).
      * Generate the code prior to running tests (checks codegen).
  

• ci: do not install deps that are in build image (c93ae50)

  This is unnecessary - the dependencies are all in the build image
  already.
  

• chore: do not check in generated test code (afc6071)

• ci: PATH changes in generator script (4c5cf33)

• ci(fix): remove ENV for protoc-gen-go (3695f14)

• ci: gobin path (9934775)

• refactor(go): rc-x509-test-harness does not reexport (d0303d9)

• revert: keep existing rx-client name (ac9c75d)

• refactor: test-harness -> test-harness-ffi (aa2295a)

  We will have more test harness crates for the other crates.