👷 New samples Gradle plugin using source sets

[LVMVRQUXL]

📝 Description

We want to move our Kotlin and Java samples from the samples Gradle subproject to dedicated source sets, named *Samples, in the types and the types-kotlinx-serialization subprojects.

The new Gradle plugin should provide the following tasks:

• checkSampleSources that checks the content of sample sources
• extractSamples that extracts samples for KDoc
• checkSampleReferences that checks sample references from KDoc
• backupMainSources that copies main sources into the build directory
• inlineSamples that inlines KDoc samples
• restoreMainSources that restores main sources from the build directory

Finally, all tasks provided by this plugin should support Kotlin and Java samples.

✅ Checklist

• 👷 Add org.kotools.samples Gradle plugin that should create source sets suffixed by Sample for Kotlin Multiplatform projects.
• 👷 Add checkSampleSources task in the new plugin.
• 👷 Add extractSamples task in the new plugin.
• 👷 Add checkSampleReferences task in the new plugin.
• 👷 Add backupMainSources task in the new plugin.
• 👷 Add restoreMainSources task in the new plugin.
• 👷 Add inlineSamples task in the new plugin.
• 👷 Configure integration of new plugin with Dokka and Kotlin.
• 👷 Use the new plugin in types-kotlinx-serialization Gradle subproject.
• 👷 Use the new plugin in types Gradle subproject.
• 🔥 Remove the org.kotools.types.samples Gradle plugin.
• 🔥 Remove the samples Gradle subproject, GitHub workflows and run configurations using it, then update the documentation referencing it in some way.