feat: support for go.work

[mdelapenya]

What does this PR do?

This PR adds support for creating a go.work file and managing it when new modules are created using the modulegen tool.

During this process, we had to rework a bit this code generation tool, using the modfile package to handle the workfile programatically. Besides that, we updated the existing tests to check the work files are properly generated, also moving tests to the right package and even removing duplicated tests (e.g. for validation).

Finally, we are improving the error messages, following recent patterns we are adopting in the library.

Important to notice the amount of lines in the changeset comes from running go work sync, which updated all the dependencies.

Why is it important?

Now the go toolchain will be able to handle the core module and its submodules in a proper manner, so it would be much easier to setup the IDE when working on the project. In the past, we generated code for VSCode and handle all the submodules, now it would be possible to just open the root dir, and because of the existence of the go.work file, the IDE would be able to follow all links across the entire code base.

Related issues

• Closes #1689

[netlify[bot]]

✅ Deploy Preview for testcontainers-go ready!

Name	Link
🔨 Latest commit	cbfdea7c474c6b563b8094ddb827abff01885f3c
🔍 Latest deploy log	https://app.netlify.com/sites/testcontainers-go/deploys/6720b6999366710008b34bb6
😎 Deploy Preview	https://deploy-preview-2849--testcontainers-go.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[mdelapenya]

@mmorel-35 pinging you for a review (if possible), as you worked in the modulegen a lot 🙏