Insert imports on copy/paste

Introduce KotlinCopyPasteReferenceProcessor

idea/testData/copyPaste/imports/ClassObjectFunInsideClass.kt

@@ -0,0 +1,13 @@
+package a
+
+// ALLOW_UNRESOLVED
+//NOTE: is is an unsupported case
+class A {
+    <selection>fun g() {
+        f()
+    }</selection>
+
+    class object {
+        fun f()
+    }
+}