* Create Code_of_conduct-ben.md
bengali translation of the Code of conduct
* Rename Code_of_conduct-ben.md to Code_of_conduct-bn.md
used bn as the language code
* Rename Code_of_conduct-bn.md to CODE_OF_CONDUCT-bn.md
* Rename CODE_OF_CONDUCT-bn.md to docs/CODE_OF_CONDUCT-bn.md
* add CoC link
Co-authored-by: Eric Hellman <eric@hellman.net>