Split catalog_export out of editor_tools

Code, locale and test suites moved from editor_tools; docs in seven languages
with screenshots where the window has something to show; own cover.

locale/ui_zh.properties

@@ -0,0 +1,14 @@
+tools/catalog_export/hint = 归档和哈希在导出时计算；JSON 写在模组归档旁边
+tools/catalog_export/mod_info = 模组
+tools/catalog_export/id = ID
+tools/catalog_export/name = 名称
+tools/catalog_export/metadata = 目录
+tools/catalog_export/locales = 本地化
+tools/catalog_export/locales_hint = 没有任何行时，使用清单中的英文名称和描述。
+tools/catalog_export/remove_locale = 移除语言
+tools/catalog_export/preview = 生成的 JSON
+tools/catalog_export/copied = JSON 已复制到剪贴板。
+tools/catalog_export/export_tip = 打包归档、计算哈希并写入目录条目的 JSON
+tools/catalog_export/exported = 已导出：{0}
+tools/catalog_export/export_error = 导出错误
+tools/catalog_export/url_required = 请设置下载 URL——没有它的目录条目毫无用处。