Translate README and CONTRIBUTING to Korean (#303)

* Create README.ko_kr.md

* Update README.ko_kr.md

* Update README.ko_kr.md

* Update README.ko_kr.md

* Update README.es.md

* Update README.pt_br.md

* Update README.zh_tw.md

* Update README.zh_tw.md

* Update README.zh_cn.md

* Update README.md

* Update README.ko_kr.md

* Korean README.md

* Korean Version of CONTRIBUTING.md

* Added Language Navigation

* Added Language Navigation

* Added Korean into Language Navigation

* Added Korean into Language Navigation

* Added Korean into Language Navigation

* Added Korean into Language Navigation

* Added Korean into Language Navigation

* Update CONTRIBUTING.ko_kr.md

* Changed to "Available in"

* Elaborated some translations

README.md

@@ -1,8 +1,8 @@
 # Apollo-11
 [![NASA][1]][2]
 
-*Available in: [English][EN], [简体中文][ZH_CN], [正體中文][ZH_TW], [Português][PT_BR], [Español][ES]*
-
+*Available in: [English][EN], [简体中文][ZH_CN], [正體中文][ZH_TW], [Português][PT_BR], [Español][ES], [한국어][KO_KR]*
+ 
 Original Apollo 11 guidance computer (AGC) source code for Command
 Module (Comanche055) and Lunar Module (Luminary099). Digitized by
 the folks at [Virtual AGC][3] and [MIT Museum][4]. The goal is to be
@@ -98,6 +98,7 @@ APPROVED:   RALPH R. RAGAN          DATE:   28 MAR 69
 [ZH_CN]:README.zh_cn.md
 [ZH_TW]:README.zh_tw.md
 [PT_BR]:README.pt_br.md
+[KO_KR]:README.ko_kr.md
 [ES]:README.es.md
 [1]:https://cdn.rawgit.com/aleen42/badges/c9246f74/src/nasa.svg
 [2]:https://www.nasa.gov/mission_pages/apollo/missions/apollo11.html