Expanded test_login.py

    - Expanded cfme/tests/test_login.py to include test_verify_password_update and test_verify_bad_password_update.

    - Also expanded login.py with more convenience functions (fill_login_fields, show_password_update_form, close_password_update_form, update_password, clear_fields)

    - Fixed (a possible typo in) area.locators['message'] locator for 5.3 in cfme/web_ui/flash.py. The previous locator did not work for me, and did not seem correct when I manually found the element in the webpage
blank space must be after `,`. I would recommend to structure this block like this for better readability
```python
password_update_form = Form(
    fields=[
        loc for loc  # I normally put `for` on new line, but it's very short so I don't do it here (no `loc` processing)
        in page.locators.items()
        if loc[0] in _password_update_form_fields],
    identifying_loc='user_verify_password')
```