Feature Request: Converting nnp -> nnb using c++ libraries

[jg-sy]

Currently, the conversion of nnp to nnb requires running nnabla_cli convert or python scripts. This is a request to add this functionality to nnabla-cpplib.

I already have a working implementation and am looking to contribute. I am posting this issue and will be creating a fork of the repository for this feature per the contributing guidelines.

[TomonobuTsujikawa]

Thanks for your interest in our project!
We will review your PR after it is created.
Also, I'll let you know here if our developers have any comments before creating your PR.