Revert "Merge pull request #3305 from doodzik/master"

This reverts commit 8677640f3375794898d17b47cee1d7276c4c1515, reversing
changes made to edcfb5718c27b85e202bcfa6934580be704ff3ee.

Conflicts:
	lib/bundler/templates/newgem/CODE_OF_CONDUCT.md.tt

This follows further discussion in
https://github.com/bundler/bundler/pull/3305 where it was pointed out
that adding this to gems without the maintainers' explicit consent and
committment to enforcement is dangerous and counter-productive.

A more thorough approach is planned in https://trello.com/c/1349U0gF