fix: convert missed AnalyzerExtension to the property API

[jeremylong]

One extension was missed in #473. This PR should complete the transition to the property API.

[jeremylong]

Note that this PR also adds the @OutputDirectory to eventually support caching. I've manually tested the output directory changes and things appear to be working correctly.

[chadlwilson]

I believe there's a much less boilerplatey (and possibly less error-prone) way to make these changes by just defining property fields by their accessor, making them abstract, and then just configuring the convention in constructor

Something like

abstract class AnalyzerExtension {
    @Input @Optional abstract Property<Boolean> getExperimentalEnabled()
    // ...
    
    AnalyzerExtension() {
        experimentalEnabled.convention(false)
        // ...
    }

Like the example at https://docs.gradle.org/current/userguide/lazy_configuration.html#where_to_apply_conventions_from

Which also avoids you needed to create getters and setters, except for any "non-standard" signatures you want to add on.

[jeremylong]

For now, I think I'll leave it with all the boilerplate code. To use the method suggested, we would need to convert several classes to interfaces and update more of the implementation.

[jeremylong]

Additional manual testing with @chadlwilson PR merged appears to work as expected.

[jeremylong]

@chadlwilson I have to take off for a few hours. Unless you object or find something else wrong - I plan on merging this later today (US East Coast time) and releasing 12.1.8.

[chadlwilson]

For now, I think I'll leave it with all the boilerplate code. To use the method suggested, we would need to convert several classes to interfaces and update more of the implementation.

I think with the magic of Groovy you just need to mark classes as abstract and change some extensions to be created via the extension creation API rather than objects.newInstance or new XXX (so they magically can get passed the relevant project references) but I agree that's not a high priority, and better to seek stability and usage first.