Implement Kotlin Script support in UAST

#KT-18353 Fixed

plugins/uast-kotlin/testData/InnerClasses.render.txt

@@ -0,0 +1,15 @@
+public final class Foo {
+    public fun Foo() = UastEmptyExpression
+    public static final class Bar {
+        private final var a: int
+        private final var b: int
+        public final fun getAPlusB() : int = a + b
+        public final fun getA() : int = UastEmptyExpression
+        public final fun getB() : int = UastEmptyExpression
+        public fun Bar(a: int, b: int) = UastEmptyExpression
+        public static final class Baz {
+            public final fun doNothing() : void = Unit
+            public fun Baz() = UastEmptyExpression
+        }
+    }
+}