Production rule: docbook -> epub

A production rule would be desirable that given a single docbook file produces an epub package. The styles are present in docbook-xsl (although without profiling). The difficulty comes from the fact that two directories are created, the images need to be copied in the proper location as an additional step, a few additional passes are required and the zip created.

The rule would receive a single file name and perform all these steps. The trickiest one could be the inclusion of the right images or auxiliary files, but parsing the opf file could help detect anomalies.

This issue is likely to be open for quite some time.

该 issue 描述了添加一条构建规则，将单个 DocBook 文件转换为 EPUB 包。首先检查 repository 中现有的构建系统，以了解规则是如何定义的。查看 docbook-xsl 样式以及所需的步骤：创建目录、复制图像、执行多次处理并创建 zip 文件。文中提到解析 OPF 文件以处理图像。检查代码库中是否已有类似规则或脚本的示例。

由索引模型根据 Issue 内容生成。