GitLab

* [R-package] made roxygen2 tags explicit and cleaned up documentation

* Apply suggestions from code review
Co-Authored-By: Nikita Titov <nekit94-08@mail.ru>

* Apply suggestions from code review
Co-Authored-By: Nikita Titov <nekit94-08@mail.ru>

* Update R-package/man/lightgbm.Rd
Co-Authored-By: Nikita Titov <nekit94-08@mail.ru>

* [R-package] moved @name to the top of roxygen blocks and removed some inaccurate information in documentation on parameters
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Add efficient demo for LightGBM

* Add bank dataset and more examples

* Add bank manual