Eighth Korean l10n work for release 1.18

- Translate tasks/administer-cluster/declare-network-policy in Korean (#22526)
- Translate tasks/debug-application-cluster/debug-init-containers in Korean (#22608)
- Fix a missing markdown syntax to enable external link (#22661)
- Translate tasks/administer-cluster/change-pv-reclaim-policy in Korean (#22551)
- Update docs/contribute/participate/ for Korean (#22605)
- Update outdated files in dev-1.18-ko.8 (#22466)
- Translate tasks/administer-cluster/dns-custom-nameservers in Korean (#22524)

Co-authored-by: Daehyun Paik <paik@a30a.dev>
Co-authored-by: Jerry Park <jaehwa@gmail.com>
Co-authored-by: bluefriday <bluefriday86@gmail.com>
Co-authored-by: June Yi <june.yi@samsung.com>
Co-authored-by: Jesang Myung <jesang.myung@gmail.com>
Co-authored-by: Seokho Son <shsongist@gmail.com>

content/ko/docs/concepts/overview/_index.md

@@ -1,4 +1,5 @@
 ---
 title: "개요"
 weight: 20
----
+description: 쿠버네티스와 그 컴포넌트에 대한 하이-레벨(high-level) 개요를 제공한다.
+---