Third Korean l10n work for release-1.15 (#15744)

* Add Link /docs/reference/ in Korean (#15610)
* Translate tasks/debug-application-cluster/resource-usage-monitoring in Korean (#15593)
* Translate tasks/inject-data-application/define-environment-variable-container in Korean (#15606)
* ko: Update outdated files in dev-1.15-ko.3 (#15605)
* Translate home/supported-doc-version in Korean (#15621)
* ko: Update some files in reference/glossary (#15631)
* Translate reference/glossary/cloud-provider.md in Korean (#15685)
* Translate docs/reference/using-api/api-overview in Korean (#15644)
* Translate tasks/debug-application-cluster/resource-metrics-pipeline in Korean (#15665)

Co-Authored-By: June Yi <june.yi@samsung.com>
Co-Authored-By: Seokho <shsongist@gmail.com>
Co-Authored-By: Tim Bannister <tim@scalefactory.com>
Co-authored-by: Yoon <learder@gmail.com>
Co-authored-by: JiMyung Lee <lee.ji.myung@gmail.com>
Co-authored-by: lapee79 <lapee79@gmail.com>
Co-authored-by: Sunghoon Kang <hoon@linecorp.com>
Co-authored-by: Yuk, Yongsu <ysyukr@gmail.com>
Co-authored-by: Lawrence Kay <me@lkaybob.pe.kr>

content/ko/docs/reference/_index.md

@@ -16,13 +16,13 @@ content_template: templates/concept
 
 ## API 레퍼런스
 
-* [쿠버네티스 API 개요](/docs/reference/using-api/api-overview/) - 쿠버네티스 API에 대한 개요
+* [쿠버네티스 API 개요](/ko/docs/reference/using-api/api-overview/) - 쿠버네티스 API에 대한 개요
 * 쿠버네티스 API 버전
+  * [1.15](/docs/reference/generated/kubernetes-api/v1.15/)
   * [1.14](/docs/reference/generated/kubernetes-api/v1.14/)
   * [1.13](/docs/reference/generated/kubernetes-api/v1.13/)
   * [1.12](/docs/reference/generated/kubernetes-api/v1.12/)
   * [1.11](/docs/reference/generated/kubernetes-api/v1.11/)
-  * [1.10](/docs/reference/generated/kubernetes-api/v1.10/)
 
 ## API 클라이언트 라이브러리