Restructure project to allow for splitting up Gradle plugin

[adam-enko]

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• Convert buildSrc to build-logic, so utils/conventions can be re-used in other included builds.
• Introduce convention plugins for common config, and publishing (replacing kotlinx.team.infra, which is not compatible with modern Gradle approaches)
• Workaround Gradle issue with running tasks in included builds https://github.com/gradle/gradle/issues/22335
• Use centralised repository definitions
• Rename subprojects to be more aligned.
• Convert 'examples' to included build, so that it can more easily depend on the 'core' projects
• Group Benchmarks runtime/generator/plugin repositories into a single included build
• Update Gradle to 8.8