Move code base to gradle/gradle

[x] import code base git history into a fork of gradle/gradle
[x] move gradle/kotlin-dsl :buildSrc to gradle/gradle :buildSrc:kotlinDsl
[x] let all gradle/kotlin-dsl subprojects become gradle/gradle subprojects
[x] split unit/integration tests into src/integTest
[x] rework integration tests to reuse gradle/gradle infrastructure
[x] add Kotlin DSL subprojects to gradle/gradle TeamCity pipeline
[x] unify @LeaksFileHandles
[x] cleanup duplicated logic in buildSrc
[x] cleanup duplicated fixtures
[x] remove Kotlin DSL version from gradle --version
[x] adapt reproducibility tests so their asserted hash change as rarely as possible
[x] let Kotlin DSL integration tests use repository mirrors on CI
[x] let parameter names metadata be generated and consumed per Gradle module
[x] update fork to Kotlin DSL 1.1.3

gradle / kotlin-dsl-samples