* [Slim4] Add OpenApiDataMocker interface template
* [Slim4] Implement scalar types in data mocker
* [Slim4] Cleanup, remove unused variables
I've rejected the idea to keep Composer dependencies in Java/codegen
variables at some point of time. It seems that after Git rebase I forgot
to delete them.
* [Slim4] Refresh samples
* [Slim4] Add pattern option to mockString method
[ref] https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.8
* [Slim4] Add enum option to mockString method
[ref] https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.20
* [Slim4] Refactor mockInteger and mockNumber tests
* [Slim4] Refactor mockString tests
* [Slim4] Use null coalescing operator
* [Slim4] Implement enum option in mockString method
* [Slim4] Add tests for enum option of mockString
