Allow reCAPTCHA for `/login`, `/lost-password` and `/confirm`

A [reCAPTCHA](https://www.google.com/recaptcha/about/) is available when using a local password for `/signup`, but not for the `/login`, `/lost-password` and `/confirm` endpoints.  This could be implemented by modifying [forms.py](https://github.com/inveniosoftware/invenio-accounts/blob/master/invenio_accounts/forms.py) as already done for `register_form_factory`.