Add option to exclude subprojects from aggregated javadoc

[Flowdalic]

Thanks for your aggregate javadoc plugin. I am currently in the process of migrating some projects of mine to buildSrc and your aggregate-javadoc plugin appears to be what I was looking for to replace an old javadocAll task of mine.

However, I would like to be able to exclude some subprojects from the aggregated javadoc. Ideally with a DSL that looks something like the following:

aggregatedJavadoc {
    excludedProjects = [
        'foo-integration-tests',
    ]
]