Build: Migrate plugin markers to maven-publish publication

libraries/tools/kotlin-gradle-plugin/build.gradle.kts

@@ -206,3 +206,5 @@ pluginBundle {
         display = "Kotlin Native plugin for CocoaPods integration"
     )
 }
+
+publishPluginMarkers()

libraries/tools/kotlin-gradle-plugin/plugin-marker/build.gradle

@@ -1,3 +0,0 @@
-apply from: "$rootDir/libraries/tools/gradle-tools/pluginMarkers.gradle"
-
-pluginMarkerProject('kotlin-gradle-plugin')