Add comprehensive wpctl documentation that generates both HTML docs and an installable man page from a single RST source.
Closes: #825🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Use custom_target() instead of configured shell scripts
* Do not copy all the .rst files in the build directory
* Setup dependencies between targets
* Tidy up dependencies lookup
* Remove unused files
* Upgrade Doxyfile to the latest version and cleanup used options