Move/copy refactoring: add base support of implicit package prefix

#KT-29720 Fixed

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

@@ -0,0 +1,8 @@
+package implicit.prefix.bar
+
+val a = 42
+
+// comment
+
+// some other comment
+val s = ""

idea/testData/refactoring/copy/copyFileFromDefaultPackageWithImpicitPrefix/after/test.kt

@@ -0,0 +1,8 @@
+package implicit.prefix
+
+val a = 42
+
+// comment
+
+// some other comment
+val s = ""

idea/testData/refactoring/copy/copyFileFromDefaultPackageWithImpicitPrefix/before/test.kt

@@ -0,0 +1,8 @@
+package implicit.prefix
+
+val a = 42
+
+// comment
+
+// some other comment
+val s = ""

idea/testData/refactoring/copy/copyFileFromDefaultPackageWithImpicitPrefix/copyFileFromDefaultPackageWithImplicitPrefix.test

@@ -0,0 +1,4 @@
+{
+  "mainFile": "test.kt",
+  "targetPackage": "bar"
+}