Rename: Support retargeting/shadowing conflict checking for functions

#KT-22564 Fixed

idea/testData/refactoring/rename/inplace/AddThis.kt

@@ -0,0 +1,10 @@
+class A {
+    fun foo() {}
+
+    fun goo() {
+        fun <caret>innerGoo() {
+            foo()
+        }
+        innerGoo()
+    }
+}

idea/testData/refactoring/rename/inplace/AddThis.kt.after

@@ -0,0 +1,10 @@
+class A {
+    fun foo() {}
+
+    fun goo() {
+        fun foo() {
+            this.foo()
+        }
+        foo()
+    }
+}

idea/testData/refactoring/rename/inplace/QualifyFun.kt

@@ -0,0 +1,8 @@
+package test
+
+fun foo() {
+    fun <caret>innerGoo() {
+        foo()
+    }
+    innerGoo()
+}

idea/testData/refactoring/rename/inplace/QualifyFun.kt.after

@@ -0,0 +1,8 @@
+package test
+
+fun foo() {
+    fun foo() {
+        test.foo()
+    }
+    innerGoo()
+}