[REQ] Allow generating only src/main/java in gradle plugin

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

When using the gradle plugin instead of creating a whole new project for java clients, I would rather just have the code generated as a precompile step and added to the classpath like https://github.com/joelittlejohn/jsonschema2pojo handles code generation.

Describe the solution you'd like

Ability to only generate the code classes in src/main/java for java clients and then the generated classes be auto referenced in the existing gradle project that's dong the code generation.

Describe alternatives you've considered

This is able as close as I've been able to come to accomplishing that with the current plugin, but it still generates a ton of extra needed stuff like the gradle project, gradle wrapper, and a bunch of other things. I would really like to be able to generate just the source code.

in build.gradle.kts

val openApiGeneratedDir = "${project.buildDir}/generated/sources/openApi"

tasks.compileJava {
    dependsOn(tasks.openApiGenerate)
}

sourceSets.main {
    java.srcDir(openApiGeneratedDir)
}

openApiGenerate {
    inputSpec.set("https://xxx.yyy.zzz")
    validateSpec.set(true)
    generatorName.set("java")
    engine.set("mustache")
    skipOverwrite.set(false)
    outputDir.set(openApiGeneratedDir)
    apiPackage.set("datalake.subscription.api")
    invokerPackage.set("datalake.subscription.invoker")
    modelPackage.set("datalake.subscription.model")
    generateApiTests.set(false)
    generateApiDocumentation.set(false)
    generateModelTests.set(false)
    generateModelDocumentation.set(false)
    configOptions.set(mapOf(
            "java8" to "true",
            "dateLibrary" to "java8",
            "library" to "native",
            "asyncNative" to "true",
            "serializationLibrary" to "jackson"
    ))

Start with the Gradle plugin configuration shown in build.gradle.kts and trace how openApiGenerate handles outputDir and generated project files. Define done as generating Java client source classes for an existing Gradle project without wrapper or other project artifacts, with those classes available through the existing source set.