Add extra configs in doxyfile generated by doxygen plugin

[jingkaimori]

Is your feature request related to a problem? Please describe.

XMake now simply add source file and project info in generated doxyfile, and there is no way to config extra options such as class graph.

Describe the solution you'd like

Add a global api set_doxygen_option in description scope, which should looks like this:

set_doxygen_option({
    case_sense_names = true,
    warning = {
        warn_if_undocument = true,
        warn_format = "$file:$line: $text"
        warn_logfile = ""
    },
    generate = {
         html = {
             -- options
         },
         rtf = false
    }
})

Describe alternatives you've considered

Add an option in xmake doxygen, which declare a custom doxyfile for this project:

xmake doxygen --doxyfile ./my/doxyfile

xmake should detect if there is duplicate config field in this file and generated file, such as PROJECT_NAME, and give proper warning.

Additional context

No response

[waruqi]

xmake does not normally all new api's for specific plugins, it is not very generic.

Add an option in xmake doxygen, which declare a custom doxyfile for this project:

You can put your custom doxyfile in the root of your project and xmake will use it first and not overwrite it.