refactor: migrate i18n files from YAML to TOML format and simplify structure (#1230)

* refactor: migrate i18n files from YAML to TOML format and simplify structure

* refactor: make translation file adjust to gohugoio/locales language code so date translation can work properly

* refactor: use hyphens instead of underscores for i18n, because that's how Hugo pick the translation file

* docs: update comments for i18n language availability and CJK language detection in hugo.toml.

i18n/ko.toml

@@ -0,0 +1,47 @@
+toggleMenu = "메뉴 여닫기"
+darkMode   = "다크 모드"
+
+[list]
+    section = "섹션"
+
+    [list.page]
+        one   = "{{ .Count }} 페이지"
+        other = "{{ .Count }} 페이지"
+
+    [list.subsection]
+        one   = "서브섹션"
+        other = "서브섹션"
+
+[article]
+    back            = "뒤로가기"
+    tableOfContents = "목차"
+    relatedContent  = "관련 글"
+    lastUpdatedOn   = "마지막 수정: "
+
+    [article.readingTime]
+        one   = "{{ .Count }} 분 정도"
+        other = "{{ .Count }} 분 정도"
+
+[notFound]
+    title    = "찾을 수 없음"
+    subtitle = "페이지를 찾을 수 없습니다."
+
+[widget]
+    [widget.archives]
+        title = "보관함"
+        more  = "더보기"
+
+    [widget.categoriesCloud]
+        title = "카테고리"
+
+    [widget.tagCloud]
+        title = "태그"
+
+[search]
+    title       = "검색"
+    placeholder = "검색어를 입력하세요..."
+    resultTitle = "#PAGES_COUNT 페이지 (#TIME_SECONDS 초)"
+
+[footer]
+    builtWith  = "{{ .Generator }}로 만듦"
+    designedBy = "{{ .DesignedBy }}의 {{ .Theme }} 테마 사용 중"