The big refactor — step 1: prep work

[rock3r]

This is the first step of "the big refactor".

In this step:

• We replace data classes in public APIs with Poko — a compiler plugin that generates equals/hashcode/toString but not methods like copy and componentN which easily break binary compatibility. This fixes Remove usage of data classes #83 (see issue for more details)
• We add the kotlinx binary-compatibility-validator plugin, that generates a list of all public APIs exposed by the published modules — the bulk of the changes in this PR are the new .api files, that track the current state of the public API (they can be skipped when reviewing). A new apiCheck is added to the check task that ensures no changes break binary compatibility by mistake.
• We add a new validatePublicApi task to published modules that breaks the check task whenever a data class is detected in the public API

---

Important

After this PR is merged, whenever adding new APIs, you need to run the apiDump method to update the .api files. If API changes are detected that are not in the .api files, the CI will fail.

[devkanro]

After this PR is merged, whenever adding new APIs, you need to run the apiDump method to update the .api files

And how about add a CI pipeline to make sure contributors updated the api files？

[rock3r]

@devkanro if you forget to update the API signatures, the ci will fail

[devkanro]

LGTM