Insert imports on copy/paste

Introduce KotlinCopyPasteReferenceProcessor

idea/testData/copyPaste/imports/ImportableEntityInExtensionLiteral.kt

@@ -0,0 +1,28 @@
+package a
+
+import a.A.Inner
+import a.A.Nested
+
+class A {
+    inner class Inner {
+    }
+    class Nested {
+    }
+    fun foo() {
+    }
+}
+
+fun A.ext() {
+}
+
+fun f(body: A.() -> Unit) {
+}
+
+<selection>fun g() {
+    f {
+        Inner()
+        Nested()
+        foo()
+        ext()
+    }
+}</selection>