Use Plugins DSL in Kotlin Gradle scripts

When plugins DSL is used, there is no need to
manually generate typesafe accessors for extensions and
conventions (by running `./gradlew kotlinDslAccessorsSnapshot`).

plugins/kapt3/kapt3-compiler/build.gradle.kts

@@ -1,8 +1,10 @@
 
 description = "Annotation Processor for Kotlin"
 
-apply { plugin("kotlin") }
-apply { plugin("jps-compatible") }
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
 
 containsEmbeddedComponents()
 

plugins/kapt3/kapt3-idea/build.gradle.kts

@@ -1,6 +1,8 @@
 
-apply { plugin("kotlin") }
-apply { plugin("jps-compatible") }
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
 
 jvmTarget = "1.6"
 

plugins/kapt3/kapt3-runtime/build.gradle.kts

@@ -1,7 +1,9 @@
 description = "Kotlin Annotation Processing Runtime"
 
-apply { plugin("kotlin") }
-apply { plugin("jps-compatible") }
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
 
 dependencies {
     compile(projectDist(":kotlin-stdlib"))