implemented W0232: Class has no __init__ method

extracted logic for "add element to statement list" into PyUtil
reused in PyMoveAttributeToInitQuickFix and PyClassHasNoInitInspection

reused AddMethodQuickFix in PyClassHasNoInitInspection

python/testData/quickFixes/AddMethodQuickFixTest/addMethodFromMethod.py

@@ -0,0 +1,11 @@
+class A:
+    def __init__(self):
+        self.x = 1
+
+    def foo(self, a):
+        self.<caret><warning descr="Unresolved attribute reference 'y' for class 'A'">y</warning>(1, a)
+
+# Some comment
+
+class B:
+    pass