Introduce new task type

[ciscoo]

The current API to create tasks is delegated to the extension. It was modeled heavily after the Maven plugin configuration:

<configuration>
    <wsdlOptions>
        <wsdlOption>
            <wsdl>${basedir}/src/main/resources/wsdl/myService.wsdl</wsdl>
        </wsdlOption>
    </wsdlOptions>
</configuration>

cxfCodegen {
    wsdl2java {
        register("myService") {
            wsdl.set(file("/src/main/resources/wsdl/myService.wsdl"))
        }
    }
}

This was done to provide a familiar API to those that were coming from Maven to Gradle. However, there are some downsides to this approach:

• Details of the task creation are hidden.
  • https://github.com/ciscoo/cxf-codegen-gradle/issues/20 may have been avoided if the user created themselves which gave them direct access to the tools/configuration rather than having to search for it.
• Disconnect between the tool options and the task
  • The tool options are generated separately from the task rather than being part/composed of the task itself.
  • Inputs/outputs need to be manually configured instead of relying on Gradle to do that work (@InputFile/@OutputDirectory)
  • Manual checking/errors for missing WSDL that can be easily avoided with @SkipWhenEmpty

Additionally, a custom task with tighter/stronger coupling to the tool options should resolve https://github.com/ciscoo/cxf-codegen-gradle/issues/7.

Finally, the current API will be deprecated in favor of the new task type.

[ciscoo]

Work on this issue has be ongoing for the last few months off/on. Specifically for #7, it has solved the compatibility issues with the Micronaut plugin.