Research for Dokka Gradle Plugin DSL 2.0

[whyoleg]

Part of #3131

Goal is to prepare for redesigning the configuration DSL. During research we will need to gather all required information from multiple sources:

• Dokka usage in various projects (big and small), f.e. gradle, aws-sdk, ktor, apollo-graphql, okio, okhttp, spring, android/androidx (?), etc:
  • think of how these projects are going to migrate to the new DSL / plugin, maybe we can add some deprecated configurations/tasks from the old plugin that will point to the new replacements
  • different formats usages
  • how it's configured
  • usage of specific features (collectors, multi-module, etc)
  • what doesn't work (and which hacks applied to fix)
• dokkatoo - provides it's own Gradle configuration layer over Dokka engine (both code and current opened issues)
• kotlinx-kover - have similar ideas (different formats, aggregation, etc)
• KGP/AGP - mature Gradle plugins with which Dokka users are very familiar
• Gradle docs on idiomatic configuration/DSL
• configuration cache and project isolation requirements
• internal UX researches and user interviews
• internal list of problems and wishes
• existing issues in Dokka with the configuration and gradle plugin tags
• any other sources which will be found interesting during review (will be added to the list afterwards)
• can spend some time on prototyping

Feel free to post any additional useful source in the comments!

[IgnatBeresnev]

The research was conducted, the next steps are internal and external review. It will be published once the document is finalized