Improve compatibility with the Gradle API, and follow best practices

Is your feature request related to a problem? Please describe

Hi, this is related to the Dokka Gradle plugin, which I would like to help improve.

Improving usage of Gradle would help with the following issues:

• https://github.com/Kotlin/dokka/issues/2231
• https://github.com/Kotlin/dokka/issues/2515
• https://github.com/Kotlin/dokka/issues/1833
• https://github.com/Kotlin/dokka/issues/1864
• https://github.com/Kotlin/dokka/issues/1752
• https://github.com/Kotlin/dokka/issues/2612
• https://github.com/Kotlin/dokka/issues/1217
• https://github.com/Kotlin/dokka/issues/1382
• https://github.com/Kotlin/dokka/issues/2286
• https://github.com/Kotlin/dokka/pull/830

This PR is related:

• https://github.com/Kotlin/dokka/pull/2499

Describe the solution you’d like

• use Kotlin DSL helpers to make the code more Kotlin-esque, for example https://github.com/Kotlin/dokka/blob/83174361becb2af227159834cdf6e14db9300c53/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/gradleConfigurations.kt#L10
• Tasks that require downloading files should cache and re-use files https://github.com/Kotlin/dokka/issues/2695
• Use configurations for sharing outputs between projects https://docs.gradle.org/7.3/samples/sample_jvm_multi_project_with_code_coverage.html
• Remove non-idiomatic helper functions https://github.com/Kotlin/dokka/blob/master/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/DokkaProperty.kt
• Rename files to match the contents, e.g. https://github.com/Kotlin/dokka/blob/master/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/main.kt
• Remove usages of internal Gradle API classes https://github.com/Kotlin/dokka/blob/83174361becb2af227159834cdf6e14db9300c53/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/AbstractDokkaLeafTask.kt#L16
• avoid using allprojects {} or subprojects {} https://github.com/Kotlin/dokka/blob/83174361becb2af227159834cdf6e14db9300c53/runners/gradle-plugin/src/test/kotlin/org/jetbrains/dokka/gradle/AbstractDokkaParentTaskTest.kt#L21-L23 https://github.com/Kotlin/dokka/blob/83174361becb2af227159834cdf6e14db9300c53/runners/gradle-plugin/src/main/kotlin/org/jetbrains/dokka/gradle/AbstractDokkaParentTask.kt#L54-L60

Describe alternatives you’ve considered A clear and concise description of any alternative solutions or features you’ve considered

Additional context

Perhaps the dokka team could create a ‘gradle-plugin’ tag for all relevant GitHub issues? https://github.com/Kotlin/dokka/issues?q=is%3Aissue+is%3Aopen++gradle

Are you willing to provide a PR?

Yes. I will try and split this up into smaller PRs.

[IgnatBeresnev]

Hi! Sorry it’s taking so long, I’ve only now finally got time after re-writing documentation for stable release.

I’ll go over all Gradle PRs in the upcoming weeks 👍

[IgnatBeresnev]

Wow… thanks! Our Gradle plugin and everything around it definitely needs work. I’ll take us some time to go through PRs, so please bear with us 😅