Create CODE_OF_CONDUCT.md
Create CODE_OF_CONDUCT.md

Summary:
Copy over the existing CoC from https://code.facebook.com/codeofconduct into the repo.

N/A

[GENERAL][FEATURE][./CODE_OF_CONDUCT.md] - Copy FB OSS CoC into repo.
Closes https://github.com/facebook/react-native/pull/16465

Differential Revision: D6167348

Pulled By: hramos

fbshipit-source-id: 5ca70a46bf7bded872c20ceb5a5941cc8d2be495

exponentjs/react-native,rickbeerendonk/react-native,janicduplessis/react-native,facebook/react-native,Bhullnatik/react-native,janicduplessis/react-native,javache/react-native,myntra/react-native,myntra/react-native,dikaiosune/react-native,kesha-antonov/react-native,arthuralee/react-native,facebook/react-native,pandiaraj44/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,Bhullnatik/react-native,myntra/react-native,hoangpham95/react-native,javache/react-native,cdlewis/react-native,rickbeerendonk/react-native,rickbeerendonk/react-native,pandiaraj44/react-native,janicduplessis/react-native,exponent/react-native,exponentjs/react-native,kesha-antonov/react-native,hoangpham95/react-native,hoastoolshop/react-native,rickbeerendonk/react-native,kesha-antonov/react-native,kesha-antonov/react-native,hammerandchisel/react-native,hoangpham95/react-native,rickbeerendonk/react-native,arthuralee/react-native,jevakallio/react-native,javache/react-native,jevakallio/react-native,pandiaraj44/react-native,hoastoolshop/react-native,cdlewis/react-native,Bhullnatik/react-native,facebook/react-native,jevakallio/react-native,hammerandchisel/react-native,facebook/react-native,myntra/react-native,exponentjs/react-native,ptmt/react-native-macos,javache/react-native,pandiaraj44/react-native,rickbeerendonk/react-native,facebook/react-native,exponentjs/react-native,ptmt/react-native-macos,hoastoolshop/react-native,arthuralee/react-native,facebook/react-native,jevakallio/react-native,exponent/react-native,hammerandchisel/react-native,hoangpham95/react-native,exponent/react-native,javache/react-native,ptmt/react-native-macos,hoastoolshop/react-native,cdlewis/react-native,arthuralee/react-native,exponentjs/react-native,myntra/react-native,kesha-antonov/react-native,dikaiosune/react-native,hoangpham95/react-native,dikaiosune/react-native,javache/react-native,hammerandchisel/react-native,myntra/react-native,pandiaraj44/react-native,hoangpham95/react-native,dikaiosune/react-native,hoastoolshop/react-native,janicduplessis/react-native,exponentjs/react-native,hoastoolshop/react-native,myntra/react-native,javache/react-native,kesha-antonov/react-native,Bhullnatik/react-native,hoangpham95/react-native,facebook/react-native,pandiaraj44/react-native,dikaiosune/react-native,javache/react-native,cdlewis/react-native,jevakallio/react-native,ptmt/react-native-macos,exponent/react-native,Bhullnatik/react-native,hammerandchisel/react-native,janicduplessis/react-native,janicduplessis/react-native,arthuralee/react-native,myntra/react-native,ptmt/react-native-macos,dikaiosune/react-native,cdlewis/react-native,ptmt/react-native-macos,cdlewis/react-native,Bhullnatik/react-native,exponent/react-native,cdlewis/react-native,kesha-antonov/react-native,dikaiosune/react-native,cdlewis/react-native,hoangpham95/react-native,myntra/react-native,pandiaraj44/react-native,rickbeerendonk/react-native,rickbeerendonk/react-native,cdlewis/react-native,facebook/react-native,exponentjs/react-native,dikaiosune/react-native,janicduplessis/react-native,hoastoolshop/react-native,Bhullnatik/react-native,ptmt/react-native-macos,hoastoolshop/react-native,exponent/react-native,jevakallio/react-native,kesha-antonov/react-native,exponent/react-native,hammerandchisel/react-native,ptmt/react-native-macos,Bhullnatik/react-native,rickbeerendonk/react-native,exponentjs/react-native,pandiaraj44/react-native,hammerandchisel/react-native,jevakallio/react-native,exponent/react-native,jevakallio/react-native,kesha-antonov/react-native,jevakallio/react-native,hammerandchisel/react-native