* update docs about how to add a new operator

This pull request adds "Build using Docker" documentation to the "Getting Started > Install and Build" menu on PaddlePaddle.org

Change the instructions to use https instead of SSH

Update the write_docs_en.rst and write_docs_cn.rst to include how to run the documentation viewer tool without Docker
Add dev/contribute_to_paddle_cn.md onto navigation link

* Add symbolic link from Paddle/CONTRIBUTING.md to doc/howto/dev/contribute_to_paddle_en.md so sphinx can generate the document
* Update CONTRIBUTING.md links so sphinx does not add these links to the TOC
* Removed dev/contribute_to_paddle_cn.md from documentation, since this document is not in sync with Paddle/CONTRIBUTING.md

* Create vlog_guide.md

* Move design/vlog_guide.md into CONTRIBUTE.md

* In response to comments from Yu Yang and Tony

* In response to comments from Luo Tao

Fixes #4445