Move `partiql-lang-kotlin` code migration examples repo under the `partiql` organization

[alancai98]

As part of #668, I created a personal repo, test-partiql-version-migration, to test code examples between different partiql-lang-kotlin major versions. It would make more sense to have this under the partiql org for future maintenance and updates. We would likely want this as part of a submodule of partiql-lang-kotlin or as a separate repo.