Move jnosql-validations project to extensions

[otaviojava]

Ref: https://github.com/eclipse/jnosql/issues/353

With the new extensions home, it is time to move jnosql-validation to the extensions repository.

Tasks

• [x] Move the project to extensions
• [x] Remove the project from Eclipse JNoSQL
• [x] Update both change logs with the change
• [ ] Move the read-me of validation to the new place.