docs(CODE_OF_CONDUCT): Added CODE_OF_CONDUCT.md
docs(CODE_OF_CONDUCT): Added CODE_OF_CONDUCT.md

Added CODE_OF_CONDUCT.md based on *Contributor Covenant Code of Conduct*
template, adapted from the Contributor Covenant, version 1.4, available
at http://contributor-covenant.org/version/1/4

gpvigano/AsImpL