Removed exceptions, found a better way to handle them.

Refactored the forms so that fields like email_address can be used in multiple forms.
Refactored form validation so that a query function is passed into the form to be run, this
way the form is not exposed to the dao layer and the query is more efficient.

This PR still requires some frontend attention. Will work with Chris to update the templates.

tests/app/main/views/test_forgot_password.py

@@ -1,3 +1,6 @@
+from flask import url_for
+
+from app.main.views import generate_token
 from tests.app.main import create_test_user
 
 
@@ -21,5 +24,20 @@ def test_should_redirect_to_password_reset_sent(notifications_admin,
     assert 'You have been sent an email containing a url to reset your password.' in response.get_data(as_text=True)
 
 
+def test_should_redirect_to_forgot_password_with_flash_message_when_token_is_expired(notifications_admin,
+                                                                                     notifications_admin_db,
+                                                                                     notify_db_session):
+    with notifications_admin.test_request_context():
+        with notifications_admin.test_client() as client:
+            notifications_admin.config['TOKEN_MAX_AGE_SECONDS'] = -1000
+            user = create_test_user('active')
+            token = generate_token(user.email_address)
+        response = client.post('/new-password/{}'.format(token),
+                               data={'new_password': 'a-new_password'})
+        assert response.status_code == 302
+        assert response.location == url_for('.forgot_password', _external=True)
+        notifications_admin.config['TOKEN_MAX_AGE_SECONDS'] = 86400
+
+
 def _set_up_mocker(mocker):
     mocker.patch("app.admin_api_client.send_email")