Add Gradle properties to included builds (#3177)

* add version-catalog def in integration-tests
* move integration-test shared utils into a subproject
* add root build.gradle.kts (even if it is empty)
* add `gradle.properties` to included builds

Author: aSemy

dokka-integration-tests/gradle.properties

@@ -0,0 +1,11 @@
+#
+# Copyright 2014-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+#
+
+# Project Settings
+# TODO remove 'dokka_version' - it doesn't need to be mandatory for non-published subprojects
+dokka_version=1.9.10-SNAPSHOT
+org.jetbrains.dokka.javaToolchain.mainCompiler=8
+org.jetbrains.dokka.javaToolchain.testLauncher=8
+org.jetbrains.dokka.kotlinLanguageLevel=1.4
+dokka_integration_test_parallelism=2

dokka-runners/cli/gradle.properties

@@ -0,0 +1,6 @@
+#
+# Copyright 2014-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+#
+
+# Project Settings
+dokka_version=1.9.10-SNAPSHOT

dokka-runners/maven-plugin/gradle.properties

@@ -0,0 +1,6 @@
+#
+# Copyright 2014-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+#
+
+# TODO remove 'dokka_version' - it doesn't need to be mandatory for non-published subprojects
+dokka_version=1.9.10-SNAPSHOT