Copy: Improve file copying

- Do not copy individual declarations if entire file is selected
  (keeping original content with comments, formatting, etc.)
- Update package directive when original file packages matches
  its directory

 #KT-20092 Fixed
 #KT-18196 Fixed

idea/testData/refactoring/copy/copyMultiClassFile/after/bar/test.kt

@@ -8,4 +8,4 @@ class A {
 class B {
     val a: A = A()
     val b: B = B()
-}
+}