restructure vars_prompt and fix regression

pushed it to use the existing propmpt from display and moved the vars prompt code there also for uniformity
changed vars_prompt to check extra vars vs the empty play.vars to restore 1.9 behaviour
sipmlified the code as it didn't need to check for syntax again (tqm is made none prior based on that)
fixes #13770

lib/ansible/utils/display.py

@@ -267,13 +267,56 @@ class Display:
             self._errors[new_msg] = 1
 
     @staticmethod
-    def prompt(msg):
+    def prompt(msg, private=False):
         prompt_string = to_bytes(msg, encoding=Display._output_encoding())
         if sys.version_info >= (3,):
             # Convert back into text on python3.  We do this double conversion
             # to get rid of characters that are illegal in the user's locale
             prompt_string = to_unicode(prompt_string)
-        return input(prompt_string)
+
+        if private:
+            return getpass.getpass(msg)
+        else:
+            return input(prompt_string)
+
+    @classmethod
+    def do_var_prompt(self, varname, private=True, prompt=None, encrypt=None, confirm=False, salt_size=None, salt=None, default=None):
+
+        result = None
+        if sys.__stdin__.isatty():
+
+            do_prompt = self.prompt
+
+            if prompt and default is not None:
+                msg = "%s [%s]: " % (prompt, default)
+            elif prompt:
+                msg = "%s: " % prompt
+            else:
+                msg = 'input for %s: ' % varname
+
+            if confirm:
+                while True:
+                    result = do_prompt(msg, private)
+                    second = do_prompt("confirm " + msg, private)
+                    if result == second:
+                        break
+                    display.display("***** VALUES ENTERED DO NOT MATCH ****")
+            else:
+                result = do_prompt(msg, private)
+        else:
+            result = None
+            display.warning("Not prompting as we are not in interactive mode")
+
+        # if result is false and default is not None
+        if not result and default is not None:
+            result = default
+
+        if encrypt:
+            result = do_encrypt(result, encrypt, salt_size, salt)
+
+        # handle utf-8 chars
+        result = to_unicode(result, errors='strict')
+        return result
 
     @staticmethod
     def _output_encoding(stderr=False):